diff --git a/DCCEXParser.cpp b/DCCEXParser.cpp
index 0335438..b07fe66 100644
--- a/DCCEXParser.cpp
+++ b/DCCEXParser.cpp
@@ -897,6 +897,7 @@ bool DCCEXParser::parseD(Print *stream, int16_t params, int16_t p[])
         StringFormatter::send(stream, F("Free memory=%d\n"), DCCTimer::getMinimumFreeMemory());
         break;
 
+#ifndef DISABLE_PROG
     case HASH_KEYWORD_ACK: // <D ACK ON/OFF> <D ACK [LIMIT|MIN|MAX|RETRY] Value>
 	if (params >= 3) {
 	    if (p[1] == HASH_KEYWORD_LIMIT) {
@@ -917,6 +918,7 @@ bool DCCEXParser::parseD(Print *stream, int16_t params, int16_t p[])
 	  Diag::ACK = onOff;
 	}
         return true;
+#endif
 
     case HASH_KEYWORD_CMD: // <D CMD ON/OFF>
         Diag::CMD = onOff;
diff --git a/version.h b/version.h
index c447973..d043e0d 100644
--- a/version.h
+++ b/version.h
@@ -6,7 +6,6 @@
 
 #define VERSION "4.2.48"
 // 4.2.48 - Add DISABLE_PROG to disable programming to save RAM/Flash
-//        - Disables all DCC-EX prog commands and EXRAIL POM, leaves IFLOCO()
 // 4.2.47 - Correct response to <JA 0>
 // 4.2.46 - Support boards with inverted fault pin
 // 4.2.45 - Add ONCLOCKMINS to FastClock to allow hourly repeat events