mempool: ignore fee estimate files from older versions

Do not load fee estimate files from before 1.14.7, because the
previous min, max and spacing parametrization will override the
newly introduced values from 35c2910

src/txmempool.cpp

@@ -909,6 +909,16 @@ CTxMemPool::ReadFeeEstimates(CAutoFile& filein)
         filein >> nVersionRequired >> nVersionThatWrote;
         if (nVersionRequired > CLIENT_VERSION)
             return error("CTxMemPool::ReadFeeEstimates(): up-version (%d) fee estimate file", nVersionRequired);
+
+        /* From 1.14.7, only accept fee estimate files created by a version equal to or higher than the
+         * minimum writer version.
+         *
+         * If in the future any of the MIN_FEERATE, MAX_FEERATE or FEE_SPACING in policy/fees.h change,
+         * or these values become configurable, this logic will need to be adapted. */
+        if (nVersionThatWrote < FEEFILE_MIN_COMPAT_VERSION_WRITER) {
+            return error("CTxMemPool::ReadFeeEstimates(): cannot re-use fee estimate files from version %d, ignoring file (non-fatal)", nVersionThatWrote);
+        }
+
         LOCK(cs);
         minerPolicyEstimator->Read(filein, nVersionThatWrote);
     }

src/txmempool.h

@@ -34,7 +34,15 @@ class CBlockIndex;
 /** Minimum client version required to read fee_estimates.dat
  * Clients with a lower version than this should ignore the file
  */
-static const int FEEFILE_MIN_BACKCOMPAT_VERSION = 139900; // 0.13.99.0
+static const int FEEFILE_MIN_BACKCOMPAT_VERSION = 1140700; // 1.14.7.0
+
+/** Minimum client version required to read fee_estimates.dat
+ * Files created with a lower version than this are ignored
+ *
+ * Due to bucket spacing and min/max changes in 1.14.7, set this
+ * to 1.14.7.0 exactly.
+ */
+static const int FEEFILE_MIN_COMPAT_VERSION_WRITER = 1140700; // 1.14.7.0
 
 inline double AllowFreeThreshold()
 {