diff --git a/bin/dnssec/dnssec-keygen.c b/bin/dnssec/dnssec-keygen.c
index c045745f63..849327e61d 100644
--- a/bin/dnssec/dnssec-keygen.c
+++ b/bin/dnssec/dnssec-keygen.c
@@ -190,7 +190,7 @@ usage(void) {
 			"(default: AUTHCONF)\n");
 	fprintf(stderr, "    -h: print usage and exit\n");
 	fprintf(stderr, "    -m <memory debugging mode>:\n");
-	fprintf(stderr, "       usage | trace | record | size | mctx\n");
+	fprintf(stderr, "       usage | trace | record\n");
 	fprintf(stderr, "    -v <level>: set verbosity level (0 - 10)\n");
 	fprintf(stderr, "    -V: print version information\n");
 	fprintf(stderr, "Timing options:\n");
diff --git a/bin/named/main.c b/bin/named/main.c
index 1f92349c48..b28d207005 100644
--- a/bin/named/main.c
+++ b/bin/named/main.c
@@ -309,7 +309,7 @@ usage(void) {
 			"             [-S sockets] [-t chrootdir] [-u "
 			"username] [-U listeners]\n"
 			"             [-m "
-			"{usage|trace|record|size|mctx}]\n"
+			"{usage|trace|record}]\n"
 			"             [-M fill|nofill]\n"
 			"usage: named [-v|-V|-C]\n");
 }
diff --git a/bin/named/named.rst b/bin/named/named.rst
index f9c7dc7532..8b71a38825 100644
--- a/bin/named/named.rst
+++ b/bin/named/named.rst
@@ -108,7 +108,7 @@ Options
 .. option:: -m flag
 
    This option turns on memory usage debugging flags. Possible flags are ``usage``,
-   ``trace``, ``record``, ``size``, and ``mctx``. These correspond to the
+   ``trace`` and ``record``. These correspond to the
    ``ISC_MEM_DEBUGXXXX`` flags described in ``<isc/mem.h>``.
 
 .. option:: -n #cpus
diff --git a/bin/tests/wire_test.c b/bin/tests/wire_test.c
index 0b1a867a14..26a84c4bac 100644
--- a/bin/tests/wire_test.c
+++ b/bin/tests/wire_test.c
@@ -62,7 +62,7 @@ fromhex(char c) {
 static void
 usage(void) {
 	fprintf(stderr, "wire_test [-b] [-d] [-p] [-r] [-s]\n");
-	fprintf(stderr, "          [-m {usage|trace|record|size|mctx}]\n");
+	fprintf(stderr, "          [-m {usage|trace|record}]\n");
 	fprintf(stderr, "          [filename]\n\n");
 	fprintf(stderr, "\t-b\tBest-effort parsing (ignore some errors)\n");
 	fprintf(stderr, "\t-d\tRead input as raw binary data\n");