diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5aec88b89..19504f9a1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -337,7 +337,7 @@ set(GNSSSDR_GNSS_SIM_LOCAL_VERSION "master")
 set(GNSSSDR_GPSTK_LOCAL_VERSION "8.0.0")
 set(GNSSSDR_MATIO_LOCAL_VERSION "1.5.21")
 set(GNSSSDR_PUGIXML_LOCAL_VERSION "1.11.4")
-set(GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION "3.19.0")
+set(GNSSSDR_PROTOCOLBUFFERS_LOCAL_VERSION "3.19.4")
 set(GNSSSDR_BENCHMARK_LOCAL_VERSION "1.6.1")
 set(GNSSSDR_MATHJAX_EXTERNAL_VERSION "2.7.7")
 
diff --git a/README.md b/README.md
index 1e80fcf0a..fa65e6356 100644
--- a/README.md
+++ b/README.md
@@ -489,9 +489,9 @@ $ sudo apt-get install autoconf automake libtool curl make g++ unzip
 and then:
 
 ```
-$ wget https://github.com/protocolbuffers/protobuf/releases/download/v3.18.0/protobuf-cpp-3.18.0.tar.gz
-$ tar xvfz protobuf-cpp-3.18.0.tar.gz
-$ cd protobuf-3.18.0
+$ wget https://github.com/protocolbuffers/protobuf/releases/download/v3.19.4/protobuf-cpp-3.19.4.tar.gz
+$ tar xvfz protobuf-cpp-3.19.4.tar.gz
+$ cd protobuf-3.19.4
 $ ./autogen.sh
 $ ./configure
 $ make