diff --git a/modules/libcom/src/yajl/yajl.c b/modules/libcom/src/yajl/yajl.c
index c21e163dd..fdad3f68e 100644
--- a/modules/libcom/src/yajl/yajl.c
+++ b/modules/libcom/src/yajl/yajl.c
@@ -74,7 +74,7 @@ yajl_alloc(const yajl_callbacks * callbacks,
     hand->lexer = NULL;
     hand->bytesConsumed = 0;
     hand->decodeBuf = yajl_buf_alloc(&(hand->alloc));
-    hand->flags     = 0;
+    hand->flags     = yajl_allow_json5 | yajl_allow_comments;
     yajl_bs_init(hand->stateStack, &(hand->alloc));
     yajl_bs_push(hand->stateStack, yajl_state_start);
 
diff --git a/modules/libcom/src/yajl/yajl_common.h b/modules/libcom/src/yajl/yajl_common.h
index d842aa5bf..fca8454a8 100644
--- a/modules/libcom/src/yajl/yajl_common.h
+++ b/modules/libcom/src/yajl/yajl_common.h
@@ -37,13 +37,27 @@ extern "C" {
  *   YAJL 1.0.12 version that was
  *   bundled with EPICS Base 3.15.0.1
  *
- * YAJL 2.1.0
+ * ***YAJL 2.1.0***
  *  \li Changes argument type for yajl_integer() from \c int to \c long \c long
- *  \li Changes argument type for yajl_string() and yajl_map_key() from \c unsigned to \c size_t
+ *  \li Changes argument type for yajl_string() and yajl_map_key() from
+ *      \c unsigned to \c size_t
  *  \li Replacement of struct yajl_parser_config with yajl_config()
  *  \li Replacement of yajl_parse_complete() with yajl_complete_parse()
+ *
+ * ***YAJL 2.2.0***
+ *   This version adds support for JSON5 parsing and generation.
+ *   The upstream YAJL repository is no longer being maintained and the
+ *   original author no longer responds to messsages, so while this code
+ *   has been offered for merging into the upstream it is unlikely that
+ *   will ever happen. The version number here is thus an EPICS-specific
+ *   construct.
  */
-#define EPICS_YAJL_VERSION VERSION_INT(2,1,0,0)
+#define EPICS_YAJL_VERSION VERSION_INT(2,2,0,0)
+
+/** A macro to make it easy to conditionally compile code that supports
+ *  older releases.
+ */
+#define HAS_JSON5
 
 /** A limit used by the generator API, YAJL_MAX_DEPTH is the maximum
  *  depth to which arrays and maps may be nested.
diff --git a/modules/libcom/src/yajl/yajl_parse.h b/modules/libcom/src/yajl/yajl_parse.h
index 09ab546ff..90367d978 100644
--- a/modules/libcom/src/yajl/yajl_parse.h
+++ b/modules/libcom/src/yajl/yajl_parse.h
@@ -183,7 +183,8 @@ extern "C" {
          * and object keys which are not permitted by the JSON standard.
          * Setting this flag tells yajl to accept JSON5 standard input.
          * This flag also enables \c yajl_allow_comments since comments are
-         * part of the JSON5 standard.
+         * part of the JSON5 standard. In the EPICS build this option is
+         * enabled by default, it must be turned off to disable JSON5.
          *
          * yajl_config() argument type: int (boolean)
          *
diff --git a/modules/libcom/test/yajl_test.c b/modules/libcom/test/yajl_test.c
index 079366680..be92aecfd 100644
--- a/modules/libcom/test/yajl_test.c
+++ b/modules/libcom/test/yajl_test.c
@@ -205,6 +205,9 @@ main(int argc, char ** argv)
     /* allocate the parser */
     hand = yajl_alloc(&callbacks, &allocFuncs, NULL);
 
+    /* turn off JSON5 (the EPICS default) */
+    yajl_config(hand, yajl_allow_json5, 0);
+
     /* check arguments.  We expect exactly one! */
     for (i=1;i<argc;i++) {
         if (!strcmp("-5", argv[i])) {