diff --git a/dev/Makefile b/dev/Makefile
index 9c880ae..d882abf 100644
--- a/dev/Makefile
+++ b/dev/Makefile
@@ -30,11 +30,11 @@ EXTENSIONS := \
 	xsl \
 	zip \
 	sockets
-ifeq (,$(findstring $(PHP_VERSION), 7.2 7.3 7.4 8.0 latest))
+ifeq (,$(findstring $(PHP_VERSION), 7.2 7.3 7.4 8.0 8.1 latest))
 	# Add more extensions to PHP < 7.2.
 	EXTENSIONS += mcrypt
 endif
-ifeq (,$(findstring $(PHP_VERSION), 7.0 7.1 7.2 7.3 7.4 8.0 latest))
+ifeq (,$(findstring $(PHP_VERSION), 7.0 7.1 7.2 7.3 7.4 8.0 8.1 latest))
 	# Add more extensions to 5.x series images.
 	EXTENSIONS += mysql
 endif