ensure minimum relay fee rate is always equal or greater than 1 sat/vb

src/main/java/com/sparrowwallet/sparrow/AppServices.java

@@ -927,7 +927,7 @@ public class AppServices {
         System.setProperty(Network.BLOCK_HEIGHT_PROPERTY, Integer.toString(currentBlockHeight));
         targetBlockFeeRates = event.getTargetBlockFeeRates();
         addMempoolRateSizes(event.getMempoolRateSizes());
-        minimumRelayFeeRate = event.getMinimumRelayFeeRate();
+        minimumRelayFeeRate = Math.max(event.getMinimumRelayFeeRate(), Transaction.DEFAULT_MIN_RELAY_FEE);
         latestBlockHeader = event.getBlockHeader();
         Config.get().addRecentServer();
     }

src/main/java/com/sparrowwallet/sparrow/wallet/SendController.java

@@ -400,6 +400,7 @@ public class SendController extends WalletFormController implements Initializabl
                 if(userFeeSet.get()) {
                     setTargetBlocks(getTargetBlocks(feeRate));
                     setFeeRangeRate(feeRate);
+                    revalidate(fee, feeListener);
                 } else {
                     setFeeValueSats(walletTransaction.getFee());
                 }