22 files changed, 326 insertions, 203 deletions

diff --git a/src/blockchain_db/berkeleydb/db_bdb.cpp b/src/blockchain_db/berkeleydb/db_bdb.cpp
index b11570e37..4d759d157 100644
--- a/src/blockchain_db/berkeleydb/db_bdb.cpp
+++ b/src/blockchain_db/berkeleydb/db_bdb.cpp
@@ -2186,34 +2186,6 @@ std::map<uint64_t, uint64_t>::BlockchainBDB::get_output_histogram(const std::vec
   throw1(DB_ERROR("Not implemented."));
 }
 
-void BlockchainBDB::set_hard_fork_starting_height(uint8_t version, uint64_t height)
-{
-    LOG_PRINT_L3("BlockchainBDB::" << __func__);
-    check_open();
-
-    Dbt_copy<uint32_t> val_key(version + 1);
-    Dbt_copy<uint64_t> val(height);
-    if (m_hf_starting_heights->put(DB_DEFAULT_TX, &val_key, &val, 0))
-        throw1(DB_ERROR("Error adding hard fork starting height to db transaction."));
-}
-
-uint64_t BlockchainBDB::get_hard_fork_starting_height(uint8_t version) const
-{
-    LOG_PRINT_L3("BlockchainBDB::" << __func__);
-    check_open();
-
-    Dbt_copy<uint32_t> key(version + 1);
-    Dbt_copy<uint64_t> result;
-
-    auto get_result = m_hf_starting_heights->get(DB_DEFAULT_TX, &key, &result, 0);
-    if (get_result == DB_NOTFOUND || get_result == DB_KEYEMPTY)
-        return std::numeric_limits<uint64_t>::max();
-    else if (get_result)
-        throw0(DB_ERROR("Error attempting to retrieve hard fork starting height from the db"));
-
-    return result;
-}
-
 void BlockchainBDB::check_hard_fork_info()
 {
   LOG_PRINT_L3("BlockchainBDB::" << __func__);
diff --git a/src/blockchain_db/berkeleydb/db_bdb.h b/src/blockchain_db/berkeleydb/db_bdb.h
index 5c6bda4eb..6bc26ed3d 100644
--- a/src/blockchain_db/berkeleydb/db_bdb.h
+++ b/src/blockchain_db/berkeleydb/db_bdb.h
@@ -385,8 +385,6 @@ private:
   virtual bool for_all_outputs(std::function<bool(uint64_t amount, const crypto::hash &tx_hash, size_t tx_idx)> f) const;
 
   // Hard fork related storage
-  virtual void set_hard_fork_starting_height(uint8_t version, uint64_t height);
-  virtual uint64_t get_hard_fork_starting_height(uint8_t version) const;
   virtual void set_hard_fork_version(uint64_t height, uint8_t version);
   virtual uint8_t get_hard_fork_version(uint64_t height) const;
   virtual void check_hard_fork_info();
diff --git a/src/blockchain_db/blockchain_db.h b/src/blockchain_db/blockchain_db.h
index 1445dd13c..ab5d2d44c 100644
--- a/src/blockchain_db/blockchain_db.h
+++ b/src/blockchain_db/blockchain_db.h
@@ -1274,27 +1274,6 @@ public:
   // Hard fork related storage
   //
 
-  // FIXME: verify that this is all correct
-  //      - TW
-  /**
-   * @brief sets the height at which a hard fork has been voted to happen
-   *
-   *
-   * @param version the version voted to fork to
-   * @param height the height of the first block on the new fork
-   */
-  virtual void set_hard_fork_starting_height(uint8_t version, uint64_t height) = 0;
-
-  /**
-   * @brief gets the height at which a hard fork has been voted to happen
-   *
-   * @param version the version to check
-   *
-   * @return the height at which the hard fork was accepted, if it has been,
-   * otherwise max(uint64_t)
-   */
-  virtual uint64_t get_hard_fork_starting_height(uint8_t version) const = 0;
-
   /**
    * @brief sets which hardfork version a height is on
    *
diff --git a/src/blockchain_db/lmdb/db_lmdb.cpp b/src/blockchain_db/lmdb/db_lmdb.cpp
index 8c51c09b1..9824d7376 100644
--- a/src/blockchain_db/lmdb/db_lmdb.cpp
+++ b/src/blockchain_db/lmdb/db_lmdb.cpp
@@ -117,13 +117,6 @@ int compare_uint64(const MDB_val *a, const MDB_val *b)
   return (va < vb) ? -1 : va > vb;
 }
 
-int compare_uint8(const MDB_val *a, const MDB_val *b)
-{
-  const uint8_t va = *(const uint8_t*)a->mv_data;
-  const uint8_t vb = *(const uint8_t*)b->mv_data;
-  return va - vb;
-};
-
 int compare_hash32(const MDB_val *a, const MDB_val *b)
 {
   uint32_t *va = (uint32_t*) a->mv_data;
@@ -1103,9 +1096,10 @@ void BlockchainLMDB::open(const std::string& filename, const int mdb_flags)
   mdb_set_dupsort(txn, m_output_txs, compare_uint64);
   mdb_set_dupsort(txn, m_block_info, compare_uint64);
 
-  mdb_set_compare(txn, m_hf_starting_heights, compare_uint8);
   mdb_set_compare(txn, m_properties, compare_string);
 
+  mdb_drop(txn, m_hf_starting_heights, 1);
+
   // get and keep current height
   MDB_stat db_stats;
   if ((result = mdb_stat(txn, m_blocks, &db_stats)))
@@ -2638,29 +2632,6 @@ std::map<uint64_t, uint64_t> BlockchainLMDB::get_output_histogram(const std::vec
 
 void BlockchainLMDB::check_hard_fork_info()
 {
-  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
-  check_open();
-
-  TXN_PREFIX(0);
-
-  MDB_stat db_stat1, db_stat2;
-  if (mdb_stat(*txn_ptr, m_blocks, &db_stat1))
-    throw0(DB_ERROR("Failed to query m_blocks"));
-  if (mdb_stat(*txn_ptr, m_hf_versions, &db_stat2))
-    throw0(DB_ERROR("Failed to query m_hf_starting_heights"));
-  if (db_stat1.ms_entries != db_stat2.ms_entries)
-  {
-    // Empty, but don't delete. This allows this function to be called after
-    // startup, after the subdbs have already been created, and rest of startup
-    // can proceed. If these don't exist, hard fork's init() will fail.
-    //
-    // If these are empty, hard fork's init() will repopulate the hard fork
-    // data.
-    mdb_drop(*txn_ptr, m_hf_starting_heights, 0);
-    mdb_drop(*txn_ptr, m_hf_versions, 0);
-  }
-
-  TXN_POSTFIX_SUCCESS();
 }
 
 void BlockchainLMDB::drop_hard_fork_info()
@@ -2676,49 +2647,6 @@ void BlockchainLMDB::drop_hard_fork_info()
   TXN_POSTFIX_SUCCESS();
 }
 
-void BlockchainLMDB::set_hard_fork_starting_height(uint8_t version, uint64_t height)
-{
-  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
-  check_open();
-
-  TXN_BLOCK_PREFIX(0);
-
-  MDB_val_copy<uint8_t> val_key(version);
-  MDB_val_copy<uint64_t> val_value(height);
-  if (auto result = mdb_put(*txn_ptr, m_hf_starting_heights, &val_key, &val_value, MDB_APPEND))
-    throw1(DB_ERROR(lmdb_error("Error adding hard fork starting height to db transaction: ", result).c_str()));
-
-  TXN_BLOCK_POSTFIX_SUCCESS();
-}
-
-uint64_t BlockchainLMDB::get_hard_fork_starting_height(uint8_t version) const
-{
-  LOG_PRINT_L3("BlockchainLMDB::" << __func__);
-  check_open();
-
-  TXN_PREFIX_RDONLY();
-
-  MDB_val_copy<uint8_t> val_key(version);
-  MDB_val val_ret;
-  uint64_t ret = 0;
-  auto result = mdb_get(m_txn, m_hf_starting_heights, &val_key, &val_ret);
-  if (result == MDB_SUCCESS)
-  {
-#ifdef MISALIGNED_OK
-    ret = *(const uint64_t*)val_ret.mv_data;
-#else
-    memcpy(&ret, val_ret.mv_data, sizeof(uint64_t));
-#endif
-  } else if (result == MDB_NOTFOUND)
-  {
-    ret = std::numeric_limits<uint64_t>::max();
-  } else if (result)
-    throw0(DB_ERROR(lmdb_error("Error attempting to retrieve a hard fork starting height from the db", result).c_str()));
-
-  TXN_POSTFIX_RDONLY();
-  return ret;
-}
-
 void BlockchainLMDB::set_hard_fork_version(uint64_t height, uint8_t version)
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
diff --git a/src/blockchain_db/lmdb/db_lmdb.h b/src/blockchain_db/lmdb/db_lmdb.h
index c7121bf63..d7a78617e 100644
--- a/src/blockchain_db/lmdb/db_lmdb.h
+++ b/src/blockchain_db/lmdb/db_lmdb.h
@@ -307,8 +307,6 @@ private:
   virtual void remove_spent_key(const crypto::key_image& k_image);
 
   // Hard fork
-  virtual void set_hard_fork_starting_height(uint8_t version, uint64_t height);
-  virtual uint64_t get_hard_fork_starting_height(uint8_t version) const;
   virtual void set_hard_fork_version(uint64_t height, uint8_t version);
   virtual uint8_t get_hard_fork_version(uint64_t height) const;
   virtual void check_hard_fork_info();
diff --git a/src/blockchain_utilities/blockchain_dump.cpp b/src/blockchain_utilities/blockchain_dump.cpp
index 6fa5ce801..23619eaeb 100644
--- a/src/blockchain_utilities/blockchain_dump.cpp
+++ b/src/blockchain_utilities/blockchain_dump.cpp
@@ -419,10 +419,6 @@ int main(int argc, char* argv[])
         for (uint64_t h = 0; h < height; ++h)
           write_pod(d, boost::lexical_cast<std::string>(h), (unsigned int)db->get_hard_fork_version(h));
       end_compound(d);
-      start_struct(d, "hf_starting_heights", true);
-        for (unsigned int v = 0; v <= 255; ++v)
-          write_pod(d, boost::lexical_cast<std::string>(v), db->get_hard_fork_starting_height(v));
-      end_compound(d);
     }
 #endif
   end_compound(d);
diff --git a/src/common/stack_trace.cpp b/src/common/stack_trace.cpp
index 0d2ccb39d..44002e2d5 100644
--- a/src/common/stack_trace.cpp
+++ b/src/common/stack_trace.cpp
@@ -38,14 +38,33 @@
 #endif
 
 // from http://stackoverflow.com/questions/11665829/how-can-i-print-stack-trace-for-caught-exceptions-in-c-code-injection-in-c
+
+// The decl of __cxa_throw in /usr/include/.../cxxabi.h uses
+// 'std::type_info *', but GCC's built-in protype uses 'void *'.
+#ifdef __clang__
+#define CXA_THROW_INFO_T std::type_info
+#else // !__clang__
+#define CXA_THROW_INFO_T void
+#endif // !__clang__
+
 #ifdef STATICLIB
 #define CXA_THROW __wrap___cxa_throw
-extern "C" void __real___cxa_throw(void *ex, void *info, void (*dest)(void*));
-#else
+extern "C"
+__attribute__((noreturn))
+void __real___cxa_throw(void *ex, CXA_THROW_INFO_T *info, void (*dest)(void*));
+#else // !STATICLIB
 #define CXA_THROW __cxa_throw
-#endif
+extern "C"
+typedef
+#ifdef __clang__ // only clang, not GCC, lets apply the attr in typedef
+__attribute__((noreturn))
+#endif // __clang__
+void (cxa_throw_t)(void *ex, CXA_THROW_INFO_T *info, void (*dest)(void*));
+#endif // !STATICLIB
 
-extern "C" void CXA_THROW(void *ex, void *info, void (*dest)(void*))
+extern "C"
+__attribute__((noreturn))
+void CXA_THROW(void *ex, CXA_THROW_INFO_T *info, void (*dest)(void*))
 {
 
   int status;
@@ -53,12 +72,13 @@ extern "C" void CXA_THROW(void *ex, void *info, void (*dest)(void*))
   tools::log_stack_trace((std::string("Exception: ")+((!status && dsym) ? dsym : (const char*)info)).c_str());
   free(dsym);
 
-#ifdef STATICLIB
+#ifndef STATICLIB
+#ifndef __clang__ // for GCC the attr can't be applied in typedef like for clang
+  __attribute__((noreturn))
+#endif // !__clang__
+   cxa_throw_t *__real___cxa_throw = (cxa_throw_t*)dlsym(RTLD_NEXT, "__cxa_throw");
+#endif // !STATICLIB
   __real___cxa_throw(ex, info, dest);
-#else
-  static void (*const rethrow)(void*, void*, void(*)(void*)) __attribute__((noreturn)) = (void(*)(void*, void*, void(*)(void*)))dlsym(RTLD_NEXT, "__cxa_throw");
-  rethrow(ex, info, dest);
-#endif
 }
 
 namespace
diff --git a/src/cryptonote_core/hardfork.cpp b/src/cryptonote_core/hardfork.cpp
index 7e2e82c4a..d3262dbe3 100644
--- a/src/cryptonote_core/hardfork.cpp
+++ b/src/cryptonote_core/hardfork.cpp
@@ -137,10 +137,6 @@ bool HardFork::add(uint8_t block_version, uint8_t voting_version, uint64_t heigh
 
   uint8_t voted = get_voted_fork_index(height + 1);
   if (voted > current_fork_index) {
-    for (int v = heights[current_fork_index].version + 1; v <= heights[voted].version; ++v) {
-      // we reached the vote threshold with this block, next one will be forked
-      db.set_hard_fork_starting_height(v, height + 1);
-    }
     current_fork_index = voted;
   }
 
@@ -172,7 +168,12 @@ void HardFork::init()
   else
     height = 1;
 
-  bool populate = db.get_hard_fork_starting_height(original_version) == std::numeric_limits<uint64_t>::max();
+  bool populate = false;
+  try
+  {
+    db.get_hard_fork_version(0);
+  }
+  catch (...) { populate = true; }
   if (populate) {
     LOG_PRINT_L0("The DB has no hard fork info, reparsing from start");
     height = 1;
@@ -182,7 +183,6 @@ void HardFork::init()
     reorganize_from_chain_height(height);
     // reorg will not touch the genesis block, use this as a flag for populating done
     db.set_hard_fork_version(0, original_version);
-    db.set_hard_fork_starting_height(original_version, 0);
   }
   else {
     rescan_from_chain_height(height);
@@ -215,7 +215,6 @@ bool HardFork::reorganize_from_block_height(uint64_t height)
   const uint64_t rescan_height = height >= (window_size - 1) ? height - (window_size  -1) : 0;
   const uint8_t start_version = height == 0 ? original_version : db.get_hard_fork_version(height);
   while (current_fork_index > 0 && heights[current_fork_index].version > start_version) {
-    db.set_hard_fork_starting_height(heights[current_fork_index].version, std::numeric_limits<uint64_t>::max());
     --current_fork_index;
   }
   for (uint64_t h = rescan_height; h <= height; ++h) {
@@ -227,10 +226,6 @@ bool HardFork::reorganize_from_block_height(uint64_t height)
 
   uint8_t voted = get_voted_fork_index(height + 1);
   if (voted > current_fork_index) {
-    for (int v = heights[current_fork_index].version + 1; v <= heights[voted].version; ++v) {
-      // we reached the vote threshold with this block, next one will be forked
-      db.set_hard_fork_starting_height(v, height + 1);
-    }
     current_fork_index = voted;
   }
 
@@ -337,12 +332,6 @@ uint8_t HardFork::get(uint64_t height) const
   return db.get_hard_fork_version(height);
 }
 
-uint64_t HardFork::get_start_height(uint8_t version) const
-{
-  CRITICAL_REGION_LOCAL(lock);
-  return db.get_hard_fork_starting_height(version);
-}
-
 uint8_t HardFork::get_current_version() const
 {
   CRITICAL_REGION_LOCAL(lock);
diff --git a/src/cryptonote_core/hardfork.h b/src/cryptonote_core/hardfork.h
index d9ef04113..b3d485878 100644
--- a/src/cryptonote_core/hardfork.h
+++ b/src/cryptonote_core/hardfork.h
@@ -155,13 +155,6 @@ namespace cryptonote
     uint8_t get(uint64_t height) const;
 
     /**
-     * @brief returns the height of the first block on the fork with th given version
-     *
-     * @param version version of the fork to query the starting block for
-     */
-    uint64_t get_start_height(uint8_t version) const;
-
-    /**
      * @brief returns the latest "ideal" version
      *
      * This is the latest version that's been scheduled
diff --git a/src/daemon/rpc_command_executor.cpp b/src/daemon/rpc_command_executor.cpp
index ae9492111..0a0fc793d 100644
--- a/src/daemon/rpc_command_executor.cpp
+++ b/src/daemon/rpc_command_executor.cpp
@@ -1123,11 +1123,9 @@ bool t_rpc_command_executor::print_bans()
         }
     }
 
-    time_t now = time(nullptr);
     for (auto i = res.bans.begin(); i != res.bans.end(); ++i)
     {
-        time_t seconds = i->seconds - now;
-        tools::msg_writer() << epee::string_tools::get_ip_string_from_int32(i->ip) << " banned for " << seconds << " seconds";
+        tools::msg_writer() << epee::string_tools::get_ip_string_from_int32(i->ip) << " banned for " << i->seconds << " seconds";
     }
 
     return true;
diff --git a/src/daemonizer/posix_fork.cpp b/src/daemonizer/posix_fork.cpp
index c068912ec..949c0f593 100644
--- a/src/daemonizer/posix_fork.cpp
+++ b/src/daemonizer/posix_fork.cpp
@@ -50,20 +50,6 @@ void fork()
   // terminal.
   setsid();
 
-  // A process inherits its working directory from its parent. This could be
-  // on a mounted filesystem, which means that the running daemon would
-  // prevent this filesystem from being unmounted. Changing to the root
-  // directory avoids this problem.
-  if (chdir("/") < 0)
-  {
-    quit("Unable to change working directory to root");
-  }
-
-  // The file mode creation mask is also inherited from the parent process.
-  // We don't want to restrict the permissions on files created by the
-  // daemon, so the mask is cleared.
-  umask(0);
-
   // A second fork ensures the process cannot acquire a controlling terminal.
   if (pid_t pid = ::fork())
   {
diff --git a/src/rpc/core_rpc_server.cpp b/src/rpc/core_rpc_server.cpp
index ca18e7e09..35200c5f9 100644
--- a/src/rpc/core_rpc_server.cpp
+++ b/src/rpc/core_rpc_server.cpp
@@ -1146,6 +1146,13 @@ namespace cryptonote
     return true;
   }
   //------------------------------------------------------------------------------------------------------------------------------
+  bool core_rpc_server::on_get_version(const COMMAND_RPC_GET_VERSION::request& req, COMMAND_RPC_GET_VERSION::response& res, epee::json_rpc::error& error_resp)
+  {
+    res.version = CORE_RPC_VERSION;
+    res.status = CORE_RPC_STATUS_OK;
+    return true;
+  }
+  //------------------------------------------------------------------------------------------------------------------------------
   bool core_rpc_server::on_fast_exit(const COMMAND_RPC_FAST_EXIT::request& req, COMMAND_RPC_FAST_EXIT::response& res)
   {
 	  cryptonote::core::set_fast_exit();
diff --git a/src/rpc/core_rpc_server.h b/src/rpc/core_rpc_server.h
index a7a54b59f..3d50c77be 100644
--- a/src/rpc/core_rpc_server.h
+++ b/src/rpc/core_rpc_server.h
@@ -107,10 +107,11 @@ namespace cryptonote
         MAP_JON_RPC_WE_IF("get_connections",     on_get_connections,            COMMAND_RPC_GET_CONNECTIONS, !m_restricted)
         MAP_JON_RPC_WE("get_info",               on_get_info_json,              COMMAND_RPC_GET_INFO)
         MAP_JON_RPC_WE("hard_fork_info",         on_hard_fork_info,             COMMAND_RPC_HARD_FORK_INFO)
-        MAP_JON_RPC_WE_IF("setbans",             on_set_bans,                   COMMAND_RPC_SETBANS, !m_restricted)
-        MAP_JON_RPC_WE_IF("getbans",             on_get_bans,                   COMMAND_RPC_GETBANS, !m_restricted)
+        MAP_JON_RPC_WE_IF("set_bans",            on_set_bans,                   COMMAND_RPC_SETBANS, !m_restricted)
+        MAP_JON_RPC_WE_IF("get_bans",            on_get_bans,                   COMMAND_RPC_GETBANS, !m_restricted)
         MAP_JON_RPC_WE_IF("flush_txpool",        on_flush_txpool,               COMMAND_RPC_FLUSH_TRANSACTION_POOL, !m_restricted)
         MAP_JON_RPC_WE("get_output_histogram",   on_get_output_histogram,       COMMAND_RPC_GET_OUTPUT_HISTOGRAM)
+        MAP_JON_RPC_WE("get_version",            on_get_version,                COMMAND_RPC_GET_VERSION)
       END_JSON_RPC_MAP()
     END_URI_MAP2()
 
@@ -153,6 +154,7 @@ namespace cryptonote
     bool on_get_bans(const COMMAND_RPC_GETBANS::request& req, COMMAND_RPC_GETBANS::response& res, epee::json_rpc::error& error_resp);
     bool on_flush_txpool(const COMMAND_RPC_FLUSH_TRANSACTION_POOL::request& req, COMMAND_RPC_FLUSH_TRANSACTION_POOL::response& res, epee::json_rpc::error& error_resp);
     bool on_get_output_histogram(const COMMAND_RPC_GET_OUTPUT_HISTOGRAM::request& req, COMMAND_RPC_GET_OUTPUT_HISTOGRAM::response& res, epee::json_rpc::error& error_resp);
+    bool on_get_version(const COMMAND_RPC_GET_VERSION::request& req, COMMAND_RPC_GET_VERSION::response& res, epee::json_rpc::error& error_resp);
     //-----------------------
 
 private:
diff --git a/src/rpc/core_rpc_server_commands_defs.h b/src/rpc/core_rpc_server_commands_defs.h
index 392c7501f..63167e249 100644
--- a/src/rpc/core_rpc_server_commands_defs.h
+++ b/src/rpc/core_rpc_server_commands_defs.h
@@ -41,6 +41,8 @@ namespace cryptonote
 #define CORE_RPC_STATUS_BUSY   "BUSY"
 #define CORE_RPC_STATUS_NOT_MINING "NOT MINING"
 
+#define CORE_RPC_VERSION 1
+
   struct COMMAND_RPC_GET_HEIGHT
   {
     struct request
@@ -1102,5 +1104,25 @@ namespace cryptonote
       END_KV_SERIALIZE_MAP()
     };
   };
+
+  struct COMMAND_RPC_GET_VERSION
+  {
+    struct request
+    {
+      BEGIN_KV_SERIALIZE_MAP()
+      END_KV_SERIALIZE_MAP()
+    };
+
+    struct response
+    {
+      std::string status;
+      uint32_t version;
+
+      BEGIN_KV_SERIALIZE_MAP()
+        KV_SERIALIZE(status)
+        KV_SERIALIZE(version)
+      END_KV_SERIALIZE_MAP()
+    };
+  };
 }
 
diff --git a/src/simplewallet/simplewallet.cpp b/src/simplewallet/simplewallet.cpp
index 4a7a70b8c..2bcd8ae4c 100644
--- a/src/simplewallet/simplewallet.cpp
+++ b/src/simplewallet/simplewallet.cpp
@@ -115,6 +115,7 @@ namespace
   const command_line::arg_descriptor<bool> arg_testnet = {"testnet", sw::tr("For testnet. Daemon must also be launched with --testnet flag"), false};
   const command_line::arg_descriptor<bool> arg_restricted = {"restricted-rpc", sw::tr("Restricts RPC to view-only commands"), false};
   const command_line::arg_descriptor<bool> arg_trusted_daemon = {"trusted-daemon", sw::tr("Enable commands which rely on a trusted daemon"), false};
+  const command_line::arg_descriptor<bool> arg_allow_mismatched_daemon_version = {"allow-mismatched-daemon-version", sw::tr("Allow communicating with a daemon that uses a different RPC version"), false};
   const command_line::arg_descriptor<uint64_t> arg_restore_height = {"restore-height", sw::tr("Restore from specific blockchain height"), 0};
 
   const command_line::arg_descriptor< std::vector<std::string> > arg_command = {"command", ""};
@@ -623,7 +624,8 @@ bool simple_wallet::help(const std::vector<std::string> &args/* = std::vector<st
 }
 
 simple_wallet::simple_wallet()
-  : m_daemon_port(0)
+  : m_allow_mismatched_daemon_version(false)
+  , m_daemon_port(0)
   , m_refresh_progress_reporter(*this)
   , m_auto_refresh_run(false)
   , m_auto_refresh_refreshing(false)
@@ -658,6 +660,8 @@ simple_wallet::simple_wallet()
   m_cmd_binder.set_handler("set_tx_note", boost::bind(&simple_wallet::set_tx_note, this, _1), tr("Set an arbitrary string note for a txid"));
   m_cmd_binder.set_handler("get_tx_note", boost::bind(&simple_wallet::get_tx_note, this, _1), tr("Get a string note for a txid"));
   m_cmd_binder.set_handler("status", boost::bind(&simple_wallet::status, this, _1), tr("Show wallet status information"));
+  m_cmd_binder.set_handler("sign", boost::bind(&simple_wallet::sign, this, _1), tr("Sign the contents of a file"));
+  m_cmd_binder.set_handler("verify", boost::bind(&simple_wallet::verify, this, _1), tr("Verify a signature on the contents of a file"));
   m_cmd_binder.set_handler("help", boost::bind(&simple_wallet::help, this, _1), tr("Show this help"));
 }
 //----------------------------------------------------------------------------------------------------
@@ -1439,18 +1443,28 @@ bool simple_wallet::handle_command_line(const boost::program_options::variables_
   m_restore_deterministic_wallet  = command_line::get_arg(vm, arg_restore_deterministic_wallet);
   m_non_deterministic             = command_line::get_arg(vm, arg_non_deterministic);
   m_trusted_daemon                = command_line::get_arg(vm, arg_trusted_daemon);
+  m_allow_mismatched_daemon_version = command_line::get_arg(vm, arg_allow_mismatched_daemon_version);
   m_restore_height                = command_line::get_arg(vm, arg_restore_height);
 
   return true;
 }
 //----------------------------------------------------------------------------------------------------
-bool simple_wallet::try_connect_to_daemon()
+bool simple_wallet::try_connect_to_daemon(bool silent)
 {
-  if (!m_wallet->check_connection())
+  bool same_version = false;
+  if (!m_wallet->check_connection(&same_version))
   {
-    fail_msg_writer() << tr("wallet failed to connect to daemon: ") << m_daemon_address << ". " <<
-      tr("Daemon either is not started or wrong port was passed. "
-      "Please make sure daemon is running or restart the wallet with the correct daemon address.");
+    if (!silent)
+      fail_msg_writer() << tr("wallet failed to connect to daemon: ") << m_daemon_address << ". " <<
+        tr("Daemon either is not started or wrong port was passed. "
+        "Please make sure daemon is running or restart the wallet with the correct daemon address.");
+    return false;
+  }
+  if (!m_allow_mismatched_daemon_version && !same_version)
+  {
+    if (!silent)
+      fail_msg_writer() << tr("Daemon uses a different RPC version that the wallet: ") << m_daemon_address << ". " <<
+        tr("Either update one of them, or use --allow-mismatched-daemon-version.");
     return false;
   }
   return true;
@@ -3207,7 +3221,8 @@ void simple_wallet::wallet_refresh_thread()
     try
     {
       uint64_t fetched_blocks;
-      m_wallet->refresh(0, fetched_blocks);
+      if (try_connect_to_daemon(true))
+        m_wallet->refresh(0, fetched_blocks);
     }
     catch(...) {}
     m_auto_refresh_refreshing = false;
@@ -3219,6 +3234,9 @@ void simple_wallet::wallet_refresh_thread()
 //----------------------------------------------------------------------------------------------------
 bool simple_wallet::run()
 {
+  // check and display warning, but go on anyway
+  try_connect_to_daemon();
+
   std::string addr_start = m_wallet->get_account().get_public_address_str(m_wallet->testnet()).substr(0, 6);
   m_auto_refresh_run = m_wallet->auto_refresh();
   if (m_auto_refresh_run)
@@ -3348,7 +3366,7 @@ bool simple_wallet::get_tx_note(const std::vector<std::string> &args)
 bool simple_wallet::status(const std::vector<std::string> &args)
 {
   uint64_t local_height = m_wallet->get_blockchain_current_height();
-  if (!m_wallet->check_connection())
+  if (!try_connect_to_daemon())
   {
     success_msg_writer() << "Refreshed " << local_height << "/?, no daemon connected";
     return true;
@@ -3368,6 +3386,71 @@ bool simple_wallet::status(const std::vector<std::string> &args)
   return true;
 }
 //----------------------------------------------------------------------------------------------------
+bool simple_wallet::sign(const std::vector<std::string> &args)
+{
+  if (args.size() != 1)
+  {
+    fail_msg_writer() << tr("usage: sign <filename>");
+    return true;
+  }
+  if (m_wallet->watch_only())
+  {
+    fail_msg_writer() << tr("wallet is watch-only and cannot sign");
+    return true;
+  }
+  std::string filename = args[0];
+  std::string data;
+  bool r = epee::file_io_utils::load_file_to_string(filename, data);
+  if (!r)
+  {
+    fail_msg_writer() << tr("failed to read file ") << filename;
+    return true;
+  }
+  std::string signature = m_wallet->sign(data);
+  success_msg_writer() << signature;
+  return true;
+}
+//----------------------------------------------------------------------------------------------------
+bool simple_wallet::verify(const std::vector<std::string> &args)
+{
+  if (args.size() != 3)
+  {
+    fail_msg_writer() << tr("usage: verify <filename> <address> <signature>");
+    return true;
+  }
+  std::string filename = args[0];
+  std::string address_string = args[1];
+  std::string signature= args[2];
+
+  std::string data;
+  bool r = epee::file_io_utils::load_file_to_string(filename, data);
+  if (!r)
+  {
+    fail_msg_writer() << tr("failed to read file ") << filename;
+    return true;
+  }
+
+  cryptonote::account_public_address address;
+  bool has_payment_id;
+  crypto::hash8 payment_id;
+  if(!get_account_integrated_address_from_str(address, has_payment_id, payment_id, m_wallet->testnet(), address_string))
+  {
+    fail_msg_writer() << tr("failed to parse address");
+    return true;
+  }
+
+  r = m_wallet->verify(data, address, signature);
+  if (!r)
+  {
+    fail_msg_writer() << tr("Bad signature from ") << address_string;
+  }
+  else
+  {
+    success_msg_writer() << tr("Good signature from ") << address_string;
+  }
+  return true;
+}
+//----------------------------------------------------------------------------------------------------
 bool simple_wallet::process_command(const std::vector<std::string> &args)
 {
   return m_cmd_binder.process_command_vec(args);
@@ -3444,6 +3527,7 @@ int main(int argc, char* argv[])
   command_line::add_arg(desc_params, arg_testnet);
   command_line::add_arg(desc_params, arg_restricted);
   command_line::add_arg(desc_params, arg_trusted_daemon);
+  command_line::add_arg(desc_params, arg_allow_mismatched_daemon_version);
   command_line::add_arg(desc_params, arg_restore_height);
   tools::wallet_rpc_server::init_options(desc_params);
 
diff --git a/src/simplewallet/simplewallet.h b/src/simplewallet/simplewallet.h
index e0478eb6e..7d8e7730c 100644
--- a/src/simplewallet/simplewallet.h
+++ b/src/simplewallet/simplewallet.h
@@ -143,9 +143,11 @@ namespace cryptonote
     bool get_tx_note(const std::vector<std::string> &args);
     bool status(const std::vector<std::string> &args);
     bool set_default_fee_multiplier(const std::vector<std::string> &args);
+    bool sign(const std::vector<std::string> &args);
+    bool verify(const std::vector<std::string> &args);
 
     uint64_t get_daemon_blockchain_height(std::string& err);
-    bool try_connect_to_daemon();
+    bool try_connect_to_daemon(bool silent = false);
     bool ask_wallet_create_if_needed();
     bool get_address_from_str(const std::string &str, cryptonote::account_public_address &address, bool &has_payment_id, crypto::hash8 &payment_id);
 
@@ -238,6 +240,7 @@ namespace cryptonote
     bool m_restore_deterministic_wallet;  // recover flag
     bool m_non_deterministic;  // old 2-random generation
     bool m_trusted_daemon;
+    bool m_allow_mismatched_daemon_version;
     uint64_t m_restore_height;  // optional
 
     std::string m_daemon_address;
diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index a153967ce..d18681f36 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -53,6 +53,7 @@ using namespace epee;
 #include "rapidjson/writer.h"
 #include "rapidjson/stringbuffer.h"
 #include "common/json_util.h"
+#include "common/base58.h"
 
 extern "C"
 {
@@ -1435,22 +1436,39 @@ bool wallet2::prepare_file_names(const std::string& file_path)
   return true;
 }
 //----------------------------------------------------------------------------------------------------
-bool wallet2::check_connection()
+bool wallet2::check_connection(bool *same_version)
 {
   boost::lock_guard<boost::mutex> lock(m_daemon_rpc_mutex);
 
-  if(m_http_client.is_connected())
-    return true;
+  if(!m_http_client.is_connected())
+  {
+    net_utils::http::url_content u;
+    net_utils::parse_url(m_daemon_address, u);
 
-  net_utils::http::url_content u;
-  net_utils::parse_url(m_daemon_address, u);
+    if(!u.port)
+    {
+      u.port = m_testnet ? config::testnet::RPC_DEFAULT_PORT : config::RPC_DEFAULT_PORT;
+    }
 
-  if(!u.port)
+    if (!m_http_client.connect(u.host, std::to_string(u.port), WALLET_RCP_CONNECTION_TIMEOUT))
+      return false;
+  }
+
+  if (same_version)
   {
-    u.port = m_testnet ? config::testnet::RPC_DEFAULT_PORT : config::RPC_DEFAULT_PORT;
+    epee::json_rpc::request<cryptonote::COMMAND_RPC_GET_VERSION::request> req_t = AUTO_VAL_INIT(req_t);
+    epee::json_rpc::response<cryptonote::COMMAND_RPC_GET_VERSION::response, std::string> resp_t = AUTO_VAL_INIT(resp_t);
+    req_t.jsonrpc = "2.0";
+    req_t.id = epee::serialization::storage_entry(0);
+    req_t.method = "get_version";
+    bool r = net_utils::invoke_http_json_remote_command2(m_daemon_address + "/json_rpc", req_t, resp_t, m_http_client);
+    if (!r || resp_t.result.status != CORE_RPC_STATUS_OK)
+      *same_version = false;
+    else
+      *same_version = resp_t.result.version == CORE_RPC_VERSION;
   }
 
-  return m_http_client.connect(u.host, std::to_string(u.port), WALLET_RCP_CONNECTION_TIMEOUT);
+  return true;
 }
 //----------------------------------------------------------------------------------------------------
 bool wallet2::generate_chacha8_key_from_secret_keys(crypto::chacha8_key &key) const
@@ -3106,6 +3124,40 @@ std::string wallet2::get_tx_note(const crypto::hash &txid) const
     return std::string();
   return i->second;
 }
+
+std::string wallet2::sign(const std::string &data) const
+{
+  crypto::hash hash;
+  crypto::cn_fast_hash(data.data(), data.size(), hash);
+  const cryptonote::account_keys &keys = m_account.get_keys();
+  crypto::signature signature;
+  crypto::generate_signature(hash, keys.m_account_address.m_spend_public_key, keys.m_spend_secret_key, signature);
+  return std::string("SigV1") + tools::base58::encode(std::string((const char *)&signature, sizeof(signature)));
+}
+
+bool wallet2::verify(const std::string &data, const cryptonote::account_public_address &address, const std::string &signature) const
+{
+  const size_t header_len = strlen("SigV1");
+  if (signature.size() < header_len || signature.substr(0, header_len) != "SigV1") {
+    LOG_PRINT_L0("Signature header check error");
+    return false;
+  }
+  crypto::hash hash;
+  crypto::cn_fast_hash(data.data(), data.size(), hash);
+  std::string decoded;
+  if (!tools::base58::decode(signature.substr(header_len), decoded)) {
+    LOG_PRINT_L0("Signature decoding error");
+    return false;
+  }
+  crypto::signature s;
+  if (sizeof(s) != decoded.size()) {
+    LOG_PRINT_L0("Signature decoding error");
+    return false;
+  }
+  memcpy(&s, decoded.data(), sizeof(s));
+  return crypto::check_signature(hash, address.m_spend_public_key, s);
+}
+
 //----------------------------------------------------------------------------------------------------
 void wallet2::generate_genesis(cryptonote::block& b) {
   if (m_testnet)
diff --git a/src/wallet/wallet2.h b/src/wallet/wallet2.h
index c5149a10c..d004b7da9 100644
--- a/src/wallet/wallet2.h
+++ b/src/wallet/wallet2.h
@@ -296,7 +296,7 @@ namespace tools
     std::vector<wallet2::pending_tx> create_transactions_2(std::vector<cryptonote::tx_destination_entry> dsts, const size_t fake_outs_count, const uint64_t unlock_time, uint64_t fee_multiplier, const std::vector<uint8_t> extra, bool trusted_daemon);
     std::vector<wallet2::pending_tx> create_transactions_all(const cryptonote::account_public_address &address, const size_t fake_outs_count, const uint64_t unlock_time, uint64_t fee_multiplier, const std::vector<uint8_t> extra, bool trusted_daemon);
     std::vector<pending_tx> create_unmixable_sweep_transactions(bool trusted_daemon);
-    bool check_connection();
+    bool check_connection(bool *same_version = NULL);
     void get_transfers(wallet2::transfer_container& incoming_transfers) const;
     void get_payments(const crypto::hash& payment_id, std::list<wallet2::payment_details>& payments, uint64_t min_height = 0) const;
     void get_payments(std::list<std::pair<crypto::hash,wallet2::payment_details>>& payments, uint64_t min_height, uint64_t max_height = (uint64_t)-1) const;
@@ -386,6 +386,9 @@ namespace tools
     void set_tx_note(const crypto::hash &txid, const std::string &note);
     std::string get_tx_note(const crypto::hash &txid) const;
 
+    std::string sign(const std::string &data) const;
+    bool verify(const std::string &data, const cryptonote::account_public_address &address, const std::string &signature) const;
+
   private:
     /*!
      * \brief  Stores wallet information to wallet file.
diff --git a/src/wallet/wallet_rpc_server.cpp b/src/wallet/wallet_rpc_server.cpp
index 01ae00fe5..5c42e1c53 100644
--- a/src/wallet/wallet_rpc_server.cpp
+++ b/src/wallet/wallet_rpc_server.cpp
@@ -168,6 +168,13 @@ namespace tools
         }
         integrated_payment_id = new_payment_id;
         cryptonote::set_encrypted_payment_id_to_tx_extra_nonce(extra_nonce, integrated_payment_id);
+
+        /* Append Payment ID data into extra */
+        if (!cryptonote::add_extra_nonce_to_tx_extra(extra, extra_nonce)) {
+          er.code = WALLET_RPC_ERROR_CODE_WRONG_PAYMENT_ID;
+          er.message = "Something went wrong with integrated payment_id.";
+          return false;
+        }
       }
     }
 
@@ -197,7 +204,7 @@ namespace tools
       /* Append Payment ID data into extra */
       if (!cryptonote::add_extra_nonce_to_tx_extra(extra, extra_nonce)) {
         er.code = WALLET_RPC_ERROR_CODE_WRONG_PAYMENT_ID;
-        er.message = "Something went wront with payment_id. Please check its format: \"" + payment_id_str + "\", expected 64-character string";
+        er.message = "Something went wrong with payment_id. Please check its format: \"" + payment_id_str + "\", expected 64-character string";
         return false;
       }
 
@@ -747,6 +754,42 @@ namespace tools
     return true;
   }
   //------------------------------------------------------------------------------------------------------------------------------
+  bool wallet_rpc_server::on_sign(const wallet_rpc::COMMAND_RPC_SIGN::request& req, wallet_rpc::COMMAND_RPC_SIGN::response& res, epee::json_rpc::error& er)
+  {
+    if (m_wallet.restricted())
+    {
+      er.code = WALLET_RPC_ERROR_CODE_DENIED;
+      er.message = "Command unavailable in restricted mode.";
+      return false;
+    }
+
+    res.signature = m_wallet.sign(req.data);
+    return true;
+  }
+  //------------------------------------------------------------------------------------------------------------------------------
+  bool wallet_rpc_server::on_verify(const wallet_rpc::COMMAND_RPC_VERIFY::request& req, wallet_rpc::COMMAND_RPC_VERIFY::response& res, epee::json_rpc::error& er)
+  {
+    if (m_wallet.restricted())
+    {
+      er.code = WALLET_RPC_ERROR_CODE_DENIED;
+      er.message = "Command unavailable in restricted mode.";
+      return false;
+    }
+
+    cryptonote::account_public_address address;
+    bool has_payment_id;
+    crypto::hash8 payment_id;
+    if(!get_account_integrated_address_from_str(address, has_payment_id, payment_id, m_wallet.testnet(), req.address))
+    {
+      er.code = WALLET_RPC_ERROR_CODE_WRONG_ADDRESS;
+      er.message = "";
+      return false;
+    }
+
+    res.good = m_wallet.verify(req.data, address, req.signature);
+    return true;
+  }
+  //------------------------------------------------------------------------------------------------------------------------------
   bool wallet_rpc_server::on_stop_wallet(const wallet_rpc::COMMAND_RPC_STOP_WALLET::request& req, wallet_rpc::COMMAND_RPC_STOP_WALLET::response& res, epee::json_rpc::error& er)
   {
     if (m_wallet.restricted())
diff --git a/src/wallet/wallet_rpc_server.h b/src/wallet/wallet_rpc_server.h
index 8c90aecfe..205896332 100644
--- a/src/wallet/wallet_rpc_server.h
+++ b/src/wallet/wallet_rpc_server.h
@@ -80,6 +80,8 @@ namespace tools
         MAP_JON_RPC_WE("set_tx_notes",       on_set_tx_notes,       wallet_rpc::COMMAND_RPC_SET_TX_NOTES)
         MAP_JON_RPC_WE("get_tx_notes",       on_get_tx_notes,       wallet_rpc::COMMAND_RPC_GET_TX_NOTES)
         MAP_JON_RPC_WE("get_transfers",      on_get_transfers,      wallet_rpc::COMMAND_RPC_GET_TRANSFERS)
+        MAP_JON_RPC_WE("sign",               on_sign,               wallet_rpc::COMMAND_RPC_SIGN)
+        MAP_JON_RPC_WE("verify",             on_verify,             wallet_rpc::COMMAND_RPC_VERIFY)
       END_JSON_RPC_MAP()
     END_URI_MAP2()
 
@@ -103,6 +105,8 @@ namespace tools
       bool on_set_tx_notes(const wallet_rpc::COMMAND_RPC_SET_TX_NOTES::request& req, wallet_rpc::COMMAND_RPC_SET_TX_NOTES::response& res, epee::json_rpc::error& er);
       bool on_get_tx_notes(const wallet_rpc::COMMAND_RPC_GET_TX_NOTES::request& req, wallet_rpc::COMMAND_RPC_GET_TX_NOTES::response& res, epee::json_rpc::error& er);
       bool on_get_transfers(const wallet_rpc::COMMAND_RPC_GET_TRANSFERS::request& req, wallet_rpc::COMMAND_RPC_GET_TRANSFERS::response& res, epee::json_rpc::error& er);
+      bool on_sign(const wallet_rpc::COMMAND_RPC_SIGN::request& req, wallet_rpc::COMMAND_RPC_SIGN::response& res, epee::json_rpc::error& er);
+      bool on_verify(const wallet_rpc::COMMAND_RPC_VERIFY::request& req, wallet_rpc::COMMAND_RPC_VERIFY::response& res, epee::json_rpc::error& er);
 
       bool handle_command_line(const boost::program_options::variables_map& vm);
 
diff --git a/src/wallet/wallet_rpc_server_commands_defs.h b/src/wallet/wallet_rpc_server_commands_defs.h
index 3908476d6..1404340da 100644
--- a/src/wallet/wallet_rpc_server_commands_defs.h
+++ b/src/wallet/wallet_rpc_server_commands_defs.h
@@ -551,6 +551,51 @@ namespace wallet_rpc
     };
   };
 
+  struct COMMAND_RPC_SIGN
+  {
+    struct request
+    {
+      std::string data;
+
+      BEGIN_KV_SERIALIZE_MAP()
+        KV_SERIALIZE(data);
+      END_KV_SERIALIZE_MAP()
+    };
+
+    struct response
+    {
+      std::string signature;
+
+      BEGIN_KV_SERIALIZE_MAP()
+        KV_SERIALIZE(signature);
+      END_KV_SERIALIZE_MAP()
+    };
+  };
+
+  struct COMMAND_RPC_VERIFY
+  {
+    struct request
+    {
+      std::string data;
+      std::string address;
+      std::string signature;
+
+      BEGIN_KV_SERIALIZE_MAP()
+        KV_SERIALIZE(data);
+        KV_SERIALIZE(address);
+        KV_SERIALIZE(signature);
+      END_KV_SERIALIZE_MAP()
+    };
+
+    struct response
+    {
+      bool good;
+
+      BEGIN_KV_SERIALIZE_MAP()
+        KV_SERIALIZE(good);
+      END_KV_SERIALIZE_MAP()
+    };
+  };
+
 }
 }
-
diff --git a/src/wallet/wallet_rpc_server_error_codes.h b/src/wallet/wallet_rpc_server_error_codes.h
index 968836671..68edfe76e 100644
--- a/src/wallet/wallet_rpc_server_error_codes.h
+++ b/src/wallet/wallet_rpc_server_error_codes.h
@@ -39,3 +39,4 @@
 #define WALLET_RPC_ERROR_CODE_TRANSFER_TYPE           -6
 #define WALLET_RPC_ERROR_CODE_DENIED                  -7
 #define WALLET_RPC_ERROR_CODE_WRONG_TXID              -8
+#define WALLET_RPC_ERROR_CODE_WRONG_SIGNATURE         -9