diff --git a/2021.09/apache/Dockerfile b/2021.09/apache/Dockerfile
index c75cf18..43993c9 100644
--- a/2021.09/apache/Dockerfile
+++ b/2021.09/apache/Dockerfile
@@ -62,7 +62,7 @@ RUN set -ex; \
     ; \
     \
 # pecl will claim success even if one install fails, so we need to perform each install separately
-    pecl install apcu-5.1.20; \
+    pecl install apcu-5.1.21; \
     pecl install memcached-3.1.5; \
     pecl install redis-5.3.4; \
     pecl install imagick-3.5.1; \
diff --git a/2021.09/fpm-alpine/Dockerfile b/2021.09/fpm-alpine/Dockerfile
index 8ddadd6..185b79a 100644
--- a/2021.09/fpm-alpine/Dockerfile
+++ b/2021.09/fpm-alpine/Dockerfile
@@ -78,7 +78,7 @@ RUN set -ex; \
     ; \
     \
 # pecl will claim success even if one install fails, so we need to perform each install separately
-    pecl install APCu-5.1.20; \
+    pecl install APCu-5.1.21; \
     pecl install memcached-3.1.5; \
     pecl install redis-5.3.4; \
     pecl install imagick-3.5.1; \
diff --git a/2021.09/fpm/Dockerfile b/2021.09/fpm/Dockerfile
index 5d5cb1b..ecef00f 100644
--- a/2021.09/fpm/Dockerfile
+++ b/2021.09/fpm/Dockerfile
@@ -62,7 +62,7 @@ RUN set -ex; \
     ; \
     \
 # pecl will claim success even if one install fails, so we need to perform each install separately
-    pecl install apcu-5.1.20; \
+    pecl install apcu-5.1.21; \
     pecl install memcached-3.1.5; \
     pecl install redis-5.3.4; \
     pecl install imagick-3.5.1; \
diff --git a/2021.12-dev/apache/Dockerfile b/2021.12-dev/apache/Dockerfile
index bd084b4..9318185 100644
--- a/2021.12-dev/apache/Dockerfile
+++ b/2021.12-dev/apache/Dockerfile
@@ -62,7 +62,7 @@ RUN set -ex; \
     ; \
     \
 # pecl will claim success even if one install fails, so we need to perform each install separately
-    pecl install apcu-5.1.20; \
+    pecl install apcu-5.1.21; \
     pecl install memcached-3.1.5; \
     pecl install redis-5.3.4; \
     pecl install imagick-3.5.1; \
diff --git a/2021.12-dev/fpm-alpine/Dockerfile b/2021.12-dev/fpm-alpine/Dockerfile
index 35bf3a1..5b5d872 100644
--- a/2021.12-dev/fpm-alpine/Dockerfile
+++ b/2021.12-dev/fpm-alpine/Dockerfile
@@ -78,7 +78,7 @@ RUN set -ex; \
     ; \
     \
 # pecl will claim success even if one install fails, so we need to perform each install separately
-    pecl install APCu-5.1.20; \
+    pecl install APCu-5.1.21; \
     pecl install memcached-3.1.5; \
     pecl install redis-5.3.4; \
     pecl install imagick-3.5.1; \
diff --git a/2021.12-dev/fpm/Dockerfile b/2021.12-dev/fpm/Dockerfile
index 7fa2145..e4b8327 100644
--- a/2021.12-dev/fpm/Dockerfile
+++ b/2021.12-dev/fpm/Dockerfile
@@ -62,7 +62,7 @@ RUN set -ex; \
     ; \
     \
 # pecl will claim success even if one install fails, so we need to perform each install separately
-    pecl install apcu-5.1.20; \
+    pecl install apcu-5.1.21; \
     pecl install memcached-3.1.5; \
     pecl install redis-5.3.4; \
     pecl install imagick-3.5.1; \