mempool: persist with XOR

src/init.cpp

@@ -458,6 +458,11 @@ void SetupServerArgs(ArgsManager& argsman)
     argsman.AddArg("-par=<n>", strprintf("Set the number of script verification threads (%u to %d, 0 = auto, <0 = leave that many cores free, default: %d)",
         -GetNumCores(), MAX_SCRIPTCHECK_THREADS, DEFAULT_SCRIPTCHECK_THREADS), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-persistmempool", strprintf("Whether to save the mempool on shutdown and load on restart (default: %u)", DEFAULT_PERSIST_MEMPOOL), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
+    argsman.AddArg("-persistmempoolv1",
+                   strprintf("Whether a mempool.dat file created by -persistmempool or the savemempool RPC will be written in the legacy format "
+                             "(version 1) or the current format (version 2). This temporary option will be removed in the future. (default: %u)",
+                             DEFAULT_PERSIST_V1_DAT),
+                   ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-pid=<file>", strprintf("Specify pid file. Relative paths will be prefixed by a net-specific datadir location. (default: %s)", BITCOIN_PID_FILENAME), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-prune=<n>", strprintf("Reduce storage requirements by enabling pruning (deleting) of old blocks. This allows the pruneblockchain RPC to be called to delete specific blocks and enables automatic pruning of old blocks if a target size in MiB is provided. This mode is incompatible with -txindex. "
             "Warning: Reverting this setting requires re-downloading the entire blockchain. "