diff --git a/Configuration.mk b/Configuration.mk
index b3cc77fe7..618302001 100644
--- a/Configuration.mk
+++ b/Configuration.mk
@@ -29,7 +29,7 @@ SIZE := -size
 
 # Library versions.
 NEWLIB_VERSION ?= 4.2.0.20211231
-LIBCPP_VERSION ?= 13.2.0
+LIBCPP_VERSION ?= 12.3.0
 
 # Set default region sizes for process memory requirements.
 STACK_SIZE       ?= 2048
diff --git a/libc++/Makefile b/libc++/Makefile
index 017942985..6fb356b90 100644
--- a/libc++/Makefile
+++ b/libc++/Makefile
@@ -1,4 +1,4 @@
-GCC_VERSION ?= 13.2.0
+GCC_VERSION ?= 12.3.0
 NEWLIB_VERSION ?= 4.2.0.20211231
 
 all: rebuild-gcc
diff --git a/libc++/README.md b/libc++/README.md
index a0664fa57..34623e318 100644
--- a/libc++/README.md
+++ b/libc++/README.md
@@ -25,7 +25,7 @@ To help ensure reproducibility, we also include a Dockerfile which can be used
 to create the libc++ libraries.
 
 ```bash
-LIBCPP=13.2.0
+LIBCPP=12.3.0
 cd libtock-c/libc++
 docker build -t libtock-c-libcpp .
 id=$(docker create libtock-c-libcpp)