diff --git a/documentation/new-notes/PR-678.md b/documentation/new-notes/PR-678.md
index bd95b4c08..26b237186 100644
--- a/documentation/new-notes/PR-678.md
+++ b/documentation/new-notes/PR-678.md
@@ -9,5 +9,4 @@ now they switch to octal mode.
 
 For backward compatibility, this behavior can be switched off, returning
 to the old decimal only conversions, by setting the environment variable
-`EPICS_DB_CONVERT_DECIMAL_ONLY` to anything except the empty string or
-strings starting with `n`, `N`, `f`, `F` or `0` before `iocInit`.
+`EPICS_DB_CONVERT_DECIMAL_ONLY` to `YES` (case insensitive) before `iocInit`.
diff --git a/modules/database/src/ioc/misc/iocInit.c b/modules/database/src/ioc/misc/iocInit.c
index fb39688cc..57f141014 100644
--- a/modules/database/src/ioc/misc/iocInit.c
+++ b/modules/database/src/ioc/misc/iocInit.c
@@ -31,6 +31,7 @@
 #include "epicsPrint.h"
 #include "epicsSignal.h"
 #include "epicsThread.h"
+#include "epicsString.h"
 #include "errMdef.h"
 #include "iocsh.h"
 #include "taskwd.h"
@@ -132,10 +133,10 @@ static int iocBuild_1(void)
     }
 
     {
-        /* fall back to "old" decimal-only conversion if EPICS_DB_CONVERT_DECIMAL_ONLY
-           is set and does not look like meaning no/false/0 */
+        /* fall back to "old" decimal-only conversion if
+           EPICS_DB_CONVERT_DECIMAL_ONLY is YES (case insensitive). */
         const char* dec_only = getenv("EPICS_DB_CONVERT_DECIMAL_ONLY");
-        if (dec_only && *dec_only && !strchr("nNfF0", *dec_only)) {
+        if (dec_only && epicsStrCaseCmp(dec_only, "YES") == 0) {
             dbConvertBase = 10;
         }
     }
diff --git a/modules/libcom/src/misc/epicsConvert.h b/modules/libcom/src/misc/epicsConvert.h
index 82e0dfcf0..6be4b5eb6 100644
--- a/modules/libcom/src/misc/epicsConvert.h
+++ b/modules/libcom/src/misc/epicsConvert.h
@@ -22,7 +22,7 @@ LIBCOM_API float epicsConvertDoubleToFloat(double value);
 
 /* dbConvertBase is used in dbPut and dbGet string to integer conversions.
    It defaults to 0 but is set to 10 if the EPICS_DB_CONVERT_DECIMAL_ONLY
-   environment variable is set.
+   environment variable is YES (case insensitive).
 */
 LIBCOM_API extern int dbConvertBase;