diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 395e51d..9a673e0 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -1,4 +1,4 @@
-nanopb-0.4.2 (2020-06-xx)
+nanopb-0.4.2 (2020-06-23)
  Fix buffer overflow when encoding bytes with size set to 65535 (#547, GHSA-3p39-mfxg-hrq4)
  Fix segfault with pointer fields and proto3_singular_msgs = true. (#504,#505)
  Fix Windows 10 temp file handling (#486)
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 31c86e7..c518c4a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,7 +2,7 @@
 
 project(nanopb C)
 
-set(nanopb_VERSION_STRING nanopb-0.4.2)
+set(nanopb_VERSION_STRING nanopb-0.4.3-dev)
 set(nanopb_SOVERSION 0)
 
 string(REPLACE "nanopb-" "" nanopb_VERSION ${nanopb_VERSION_STRING})
diff --git a/conanfile.py b/conanfile.py
index c1683ec..d709236 100644
--- a/conanfile.py
+++ b/conanfile.py
@@ -3,7 +3,7 @@
 
 class NanoPbConan(ConanFile):
     name = "nanopb"
-    version = "0.4.2"
+    version = "0.4.3-dev"
     license = "zlib"
     url = "https://jpa.kapsi.fi/nanopb/"
     description = "Protocol Buffers with small code size"
diff --git a/extra/poetry/pyproject.toml b/extra/poetry/pyproject.toml
index 75d0d47..29d1282 100644
--- a/extra/poetry/pyproject.toml
+++ b/extra/poetry/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "nanopb"
-version = "0.4.2"
+version = "0.4.3-dev"
 description = "Nanopb is a small code-size Protocol Buffers implementation in ansi C. It is especially suitable for use in microcontrollers, but fits any memory restricted system."
 authors = ["Petteri Aimonen <jpa@npb.mail.kapsi.fi>"]
 license = "Zlib"
diff --git a/generator/nanopb_generator.py b/generator/nanopb_generator.py
index da878eb..400b8e7 100755
--- a/generator/nanopb_generator.py
+++ b/generator/nanopb_generator.py
@@ -4,7 +4,7 @@
 from __future__ import unicode_literals
 
 '''Generate header file for nanopb from a ProtoBuf FileDescriptorSet.'''
-nanopb_version = "nanopb-0.4.2"
+nanopb_version = "nanopb-0.4.3-dev"
 
 import sys
 import re
diff --git a/pb.h b/pb.h
index 65787c7..cc78303 100644
--- a/pb.h
+++ b/pb.h
@@ -55,7 +55,7 @@
 
 /* Version of the nanopb library. Just in case you want to check it in
  * your own program. */
-#define NANOPB_VERSION nanopb-0.4.2
+#define NANOPB_VERSION nanopb-0.4.3-dev
 
 /* Include all the system headers needed by nanopb. You will need the
  * definitions of the following: