diff --git a/dev-libs/protobuf-31.1.PKGBUILD b/dev-libs/protobuf-31.1.PKGBUILD
new file mode 100644
index 0000000..dcedebd
--- /dev/null
+++ b/dev-libs/protobuf-31.1.PKGBUILD
@@ -0,0 +1,58 @@
+pkgname=protobuf
+pkgver=31.1
+pkgdesc="Google's Protocol Buffers - Extensible mechanism for serializing structured data"
+homepage="https://protobuf.dev/"
+license=("BSD")
+depends=(abseil-cpp zlib)
+_patches=("${pkgname}-30.0-findJsonCpp.patch")
+_patch_sums=("e3212111ada7f0a9dba717c70a9257b366a9cb6dfecfbcb67cf76645dcecf653cfb23b99ac394be16fa9c3baa8439be59ef5fa64631f31263da6c82c875665a5")
+sources=("${pkgname}-${pkgver}.tar.gz"
+  "FindJsonCpp.cmake"
+  "${_patches[@]}"
+)
+urls=("https://github.com/protocolbuffers/protobuf/releases/download/v${pkgver}/${sources[0]}"
+  "FindJsonCpp.cmake"
+  "${_patches[@]}"
+)
+sha512sums=("5bf730e37183defcb29cf4831128f536ad8bcdce2b2b46b297d95f3de4a037b9ff3b6c57df66a039256dcefd828ba9d43c32b01a7a82aa5c881a9ae12cadb643"
+  "4a824ac0a73eebf622f999c4a78add515fea92eb44e6a1bc754343567e747f5258ca0d1c600644c67691583779a9cad814a6daf983e666c389fcaa90a2ec0aa6"
+  "${_patch_sums[@]}"
+)
+
+src_prepare() {
+  tar -xf ${distdir}/${sources[0]} --strip-components=1
+  for _patch in ${_patches[@]}; do
+    patch -p1 -i ${filedir}/${_patch}
+  done
+  cp "${filedir}/FindJsonCpp.cmake" cmake
+}
+
+src_build() {
+  local cmake_args=(
+    -D CMAKE_BUILD_TYPE=release
+    -D CMAKE_INSTALL_PREFIX=/usr
+    -D protobuf_BUILD_CONFORMANCE=no
+    -D protobuf_BUILD_LIBPROTOC=yes
+    -D protobuf_BUILD_LIBUPB=yes
+    -D protobuf_BUILD_PROTOBUF_BINARIES=yes
+    -D protobuf_BUILD_PROTOC_BINARIES=yes
+    -D protobuf_BUILD_SHARED_LIBS="yes"
+    -D protobuf_BUILD_TESTS=no
+    -D protobuf_DISABLE_RTTI="no"
+    -D protobuf_INSTALL="yes"
+    -D protobuf_TEST_XML_OUTDIR=no
+    -D protobuf_WITH_ZLIB=yes
+    -D protobuf_VERBOSE=no
+    -D CMAKE_MODULE_PATH="cmake"
+    -D protobuf_LOCAL_DEPENDENCIES_ONLY="yes"
+  )
+  cmake -B build "${cmake_args[@]}"
+  cmake --build build
+}
+
+src_install() {
+  DESTDIR="$pkgdir" cmake --install build
+  install -vDm644 editors/proto.vim -t "${pkgdir}"/usr/share/vim/vimfiles/syntax
+}
+
+# vim:ft=sh syn=sh et sw=2:
diff --git a/dev-libs/protobuf-31.1/FindJsonCpp.cmake b/dev-libs/protobuf-31.1/FindJsonCpp.cmake
new file mode 100644
index 0000000..8fff533
--- /dev/null
+++ b/dev-libs/protobuf-31.1/FindJsonCpp.cmake
@@ -0,0 +1,40 @@
+find_path(JsonCpp_INCLUDE_DIR "json/json.h"
+  PATH_SUFFIXES "jsoncpp"
+  DOC "jsoncpp include directory")
+mark_as_advanced(JsonCpp_INCLUDE_DIR)
+
+find_library(JsonCpp_LIBRARY
+  NAMES jsoncpp
+  DOC "jsoncpp library")
+mark_as_advanced(JsonCpp_LIBRARY)
+
+if (JsonCpp_INCLUDE_DIR AND EXISTS "${JsonCpp_INCLUDE_DIR}/json/version.h")
+  file(STRINGS "${JsonCpp_INCLUDE_DIR}/json/version.h" _JsonCpp_version_lines
+    REGEX "JSONCPP_VERSION_[A-Z]+")
+  string(REGEX REPLACE ".*# *define +JSONCPP_VERSION_MAJOR +([0-9]+).*" "\\1" _JsonCpp_version_major "${_JsonCpp_version_lines}")
+  string(REGEX REPLACE ".*# *define +JSONCPP_VERSION_MINOR +([0-9]+).*" "\\1" _JsonCpp_version_minor "${_JsonCpp_version_lines}")
+  string(REGEX REPLACE ".*# *define +JSONCPP_VERSION_PATCH +([0-9]+).*" "\\1" _JsonCpp_version_patch "${_JsonCpp_version_lines}")
+  set(JsonCpp_VERSION "${_JsonCpp_version_major}.${_JsonCpp_version_minor}.${_JsonCpp_version_patch}")
+  unset(_JsonCpp_version_major)
+  unset(_JsonCpp_version_minor)
+  unset(_JsonCpp_version_patch)
+  unset(_JsonCpp_version_lines)
+endif ()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(JsonCpp
+  REQUIRED_VARS JsonCpp_LIBRARY JsonCpp_INCLUDE_DIR
+  VERSION_VAR JsonCpp_VERSION)
+
+if (JsonCpp_FOUND)
+  set(JsonCpp_INCLUDE_DIRS "${JsonCpp_INCLUDE_DIR}")
+  set(JsonCpp_LIBRARIES "${JsonCpp_LIBRARY}")
+
+  if (NOT TARGET JsonCpp::JsonCpp)
+    add_library(JsonCpp::JsonCpp SHARED IMPORTED)
+    set_target_properties(JsonCpp::JsonCpp PROPERTIES
+      IMPORTED_LOCATION "${JsonCpp_LIBRARY}"
+      IMPORTED_IMPLIB "${JsonCpp_LIBRARY}"
+      INTERFACE_INCLUDE_DIRECTORIES "${JsonCpp_INCLUDE_DIR}")
+  endif ()
+endif ()
diff --git a/dev-libs/protobuf-31.1/protobuf-30.0-findJsonCpp.patch b/dev-libs/protobuf-31.1/protobuf-30.0-findJsonCpp.patch
new file mode 100644
index 0000000..9848a61
--- /dev/null
+++ b/dev-libs/protobuf-31.1/protobuf-30.0-findJsonCpp.patch
@@ -0,0 +1,44 @@
+From 2fe6cac5797bead74c473c795fdc5f9d50703894 Mon Sep 17 00:00:00 2001
+From: Paul Zander <negril.nx+gentoo@gmail.com>
+Date: Thu, 6 Mar 2025 13:19:01 +0100
+Subject: [PATCH] fix JsonCPP name
+
+Signed-off-by: Paul Zander <negril.nx+gentoo@gmail.com>
+
+diff --git a/cmake/conformance.cmake b/cmake/conformance.cmake
+index 7377841..dba05aa 100644
+--- a/cmake/conformance.cmake
++++ b/cmake/conformance.cmake
+@@ -1,9 +1,9 @@
+ # Don't run jsoncpp tests.
+ set(JSONCPP_WITH_TESTS OFF)
+ 
+-if (NOT TARGET jsoncpp_lib)
++if (NOT TARGET JsonCpp::JsonCpp)
+   if (NOT protobuf_FORCE_FETCH_DEPENDENCIES)
+-    find_package(jsoncpp)
++    find_package(JsonCpp)
+   endif()
+ 
+   # Fallback to fetching Googletest from github if it's not found locally.
+@@ -21,7 +21,7 @@ if (NOT TARGET jsoncpp_lib)
+   endif()
+ endif()
+ 
+-if (NOT TARGET jsoncpp_lib)
++if (NOT TARGET JsonCpp::JsonCpp)
+   message(FATAL_ERROR
+           "Cannot find jsoncpp dependency that's needed to build conformance tests.\n"
+           "If instead you want to skip these tests, run cmake with:\n"
+@@ -151,7 +151,7 @@ add_test(NAME conformance_cpp_test
+ set(JSONCPP_WITH_TESTS OFF CACHE BOOL "Disable tests")
+ 
+ if(BUILD_SHARED_LIBS)
+-  target_link_libraries(conformance_test_runner jsoncpp_lib)
++  target_link_libraries(conformance_test_runner JsonCpp::JsonCpp)
+ else()
+   target_link_libraries(conformance_test_runner jsoncpp_static)
+ endif()
+-- 
+2.48.1
+