diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 28be095cb3..268eff68b8 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -13,11 +13,13 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        os: [alpine-3.17, ubuntu-20.04, ubuntu-22.04]
+        os: [alpine-3.17, alpine-3.21, ubuntu-20.04, ubuntu-22.04]
         platform: [linux/amd64]
         include:
           - os: alpine-3.17
             platform: linux/arm64
+          - os: alpine-3.21
+            platform: linux/arm64
     steps:
       - name: Checkout repository
         uses: actions/checkout@v3
diff --git a/Earthfile b/Earthfile
index e19cb9f550..a0f126b1cf 100644
--- a/Earthfile
+++ b/Earthfile
@@ -10,6 +10,16 @@ alpine-3.17:
       rm -rf /var/cache/apk/*
   RUN apk add openjdk8-jre
 
+alpine-3.21:
+  FROM --platform=$BUILDPLATFORM alpine:3.21
+  RUN apk add --no-progress --update git build-base zip
+  RUN apk --no-cache --update add libgcc libstdc++ \
+      git make g++ \
+      build-base gtest gtest-dev boost boost-dev protobuf protobuf-dev cmake icu icu-dev openssl \
+      && \
+      rm -rf /var/cache/apk/*
+  RUN apk add openjdk8-jre
+
 ubuntu-20.04:
   FROM --platform=$BUILDPLATFORM ubuntu:20.04
   RUN apt-get update && apt-get -y upgrade
@@ -51,6 +61,7 @@ libphonenumber:
   RUN make install
 
   WORKDIR assets
+  RUN rm -rf lib/cmake
   RUN zip -r ../libphonenumber_${TARGETARCH}-${buildos}.zip *
 
   SAVE ARTIFACT /libphonenumber/cpp/build/libphonenumber_${TARGETARCH}-${buildos}.zip AS LOCAL cpp/build/libphonenumber_${TARGETARCH}-${buildos}.zip
diff --git a/cpp/CMakeLists.txt b/cpp/CMakeLists.txt
index 27e4680ccc..48d65e98bf 100644
--- a/cpp/CMakeLists.txt
+++ b/cpp/CMakeLists.txt
@@ -102,10 +102,12 @@ endif ()
 # Find all the required libraries and programs.
 find_package(absl)
 
+set (ABSL_LIB absl::node_hash_set absl::strings absl::synchronization)
+
 if(NOT absl_FOUND)
   # Overide abseil install rules for subprojects
   set(ABSL_ENABLE_INSTALL ON)
-  
+
   # Downloading the abseil sources at particular version to not catch up
   # with its new build requirements like min C++14 is mandated in that lib.
   FetchContent_Declare(
@@ -128,7 +130,11 @@ if(NOT absl_FOUND)
   # https://github.com/abseil/abseil-cpp/issues/225
   set(CMAKE_POSITION_INDEPENDENT_CODE TRUE)
   add_subdirectory(${abseil-cpp_SOURCE_DIR} ${abseil-cpp_BINARY_DIR})
-endif()
+else ()
+  # Alpine 3.21, absl installed by default,
+  # protobuf generated with ABSL_DCHECK macros, so we need 'absl_check' deps
+  list (APPEND ABSL_LIB absl::absl_check)
+endif ()
 
 if (BUILD_TESTING)
   include (../tools/cpp/gtest.cmake)
@@ -427,7 +433,7 @@ include_directories ("src")
 # Collate dependencies
 #----------------------------------------------------------------
 
-set (LIBRARY_DEPS ${ICU_LIB} ${PROTOBUF_LIB} absl::node_hash_set absl::strings absl::synchronization)
+set (LIBRARY_DEPS ${ICU_LIB} ${PROTOBUF_LIB} ${ABSL_LIB})
 
 if (USE_BOOST)
   list (APPEND LIBRARY_DEPS ${Boost_LIBRARIES})