diff --git a/2.6/alpine3.13/Dockerfile b/2.6/alpine3.15/Dockerfile
similarity index 92%
rename from 2.6/alpine3.13/Dockerfile
rename to 2.6/alpine3.15/Dockerfile
index 4f2440a2b..172918f13 100644
--- a/2.6/alpine3.13/Dockerfile
+++ b/2.6/alpine3.15/Dockerfile
@@ -4,7 +4,7 @@
 # PLEASE DO NOT EDIT IT DIRECTLY.
 #
 
-FROM alpine:3.13
+FROM alpine:3.15
 
 RUN set -eux; \
 	apk add --no-cache \
@@ -83,6 +83,12 @@ RUN set -eux; \
 	patch -p1 -i thread-stack-fix.patch; \
 	rm thread-stack-fix.patch; \
 	\
+# https://bugs.ruby-lang.org/issues/17723 (building with autoconf 2.70+ fails)
+# https://github.com/ruby/ruby/pull/3773
+	wget -O 'autoconf-2.70.patch' 'https://github.com/ruby/ruby/commit/fcc88da5eb162043adcba552646677d2ab5adf55.patch'; \
+	patch -p1 -i autoconf-2.70.patch; \
+	rm autoconf-2.70.patch; \
+	\
 # the configure script does not detect isnan/isinf as macros
 	export ac_cv_func_isnan=yes ac_cv_func_isinf=yes; \
 	\
diff --git a/2.7/alpine3.13/Dockerfile b/2.7/alpine3.15/Dockerfile
similarity index 99%
rename from 2.7/alpine3.13/Dockerfile
rename to 2.7/alpine3.15/Dockerfile
index 0d7517b55..487142a3b 100644
--- a/2.7/alpine3.13/Dockerfile
+++ b/2.7/alpine3.15/Dockerfile
@@ -4,7 +4,7 @@
 # PLEASE DO NOT EDIT IT DIRECTLY.
 #
 
-FROM alpine:3.13
+FROM alpine:3.15
 
 RUN set -eux; \
 	apk add --no-cache \
diff --git a/3.0/alpine3.13/Dockerfile b/3.0/alpine3.15/Dockerfile
similarity index 99%
rename from 3.0/alpine3.13/Dockerfile
rename to 3.0/alpine3.15/Dockerfile
index c52c6d4b0..8b6b48505 100644
--- a/3.0/alpine3.13/Dockerfile
+++ b/3.0/alpine3.15/Dockerfile
@@ -4,7 +4,7 @@
 # PLEASE DO NOT EDIT IT DIRECTLY.
 #
 
-FROM alpine:3.13
+FROM alpine:3.15
 
 RUN set -eux; \
 	apk add --no-cache \
diff --git a/3.1-rc/alpine3.13/Dockerfile b/3.1-rc/alpine3.15/Dockerfile
similarity index 99%
rename from 3.1-rc/alpine3.13/Dockerfile
rename to 3.1-rc/alpine3.15/Dockerfile
index 2073ef1d1..74a45c220 100644
--- a/3.1-rc/alpine3.13/Dockerfile
+++ b/3.1-rc/alpine3.15/Dockerfile
@@ -4,7 +4,7 @@
 # PLEASE DO NOT EDIT IT DIRECTLY.
 #
 
-FROM alpine:3.13
+FROM alpine:3.15
 
 RUN set -eux; \
 	apk add --no-cache \
diff --git a/versions.json b/versions.json
index 1109e4a6f..f479e9023 100644
--- a/versions.json
+++ b/versions.json
@@ -6,8 +6,8 @@
       "slim-bullseye",
       "buster",
       "slim-buster",
-      "alpine3.14",
-      "alpine3.13"
+      "alpine3.15",
+      "alpine3.14"
     ],
     "version": "2.6.9"
   },
@@ -18,8 +18,8 @@
       "slim-bullseye",
       "buster",
       "slim-buster",
-      "alpine3.14",
-      "alpine3.13"
+      "alpine3.15",
+      "alpine3.14"
     ],
     "version": "2.7.5"
   },
@@ -30,8 +30,8 @@
       "slim-bullseye",
       "buster",
       "slim-buster",
-      "alpine3.14",
-      "alpine3.13"
+      "alpine3.15",
+      "alpine3.14"
     ],
     "version": "3.0.3"
   },
@@ -42,8 +42,8 @@
       "slim-bullseye",
       "buster",
       "slim-buster",
-      "alpine3.14",
-      "alpine3.13"
+      "alpine3.15",
+      "alpine3.14"
     ],
     "version": "3.1.0-preview1"
   }
diff --git a/versions.sh b/versions.sh
index 51d1803e2..5e217eead 100755
--- a/versions.sh
+++ b/versions.sh
@@ -72,8 +72,8 @@ for version in "${versions[@]}"; do
 					"buster"
 				| ., "slim-" + .), # https://github.com/docker-library/ruby/pull/142#issuecomment-320012893
 				(
-					"3.14",
-					"3.13"
+					"3.15",
+					"3.14"
 				| "alpine" + .)
 			],
 		}