diff --git a/CHANGELOG.md b/CHANGELOG.md
index a6a9735c..5ba27ebf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,8 @@
 
 The espeak-ng project is a fork of the espeak project.
 
+### 1.51 (In Development)
+
 ### 1.50 - 2019-11-30
 
 *  Add a `--disable-rpath` option to prevent libtool hardcoding rpaths in the executable.
diff --git a/android/jni/include/config.h b/android/jni/include/config.h
index 9f070864..edae8175 100644
--- a/android/jni/include/config.h
+++ b/android/jni/include/config.h
@@ -1,2 +1,2 @@
 // This is created by autoconf on POSIX-compatibe build environments.
-#define PACKAGE_VERSION "1.50"
+#define PACKAGE_VERSION "1.51-dev"
diff --git a/configure.ac b/configure.ac
index 798c922f..bb124bb3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,5 +1,5 @@
 AC_PREREQ([2.63])
-AC_INIT([eSpeak NG], [1.50], [https://github.com/espeak-ng/espeak-ng/issues], [espeak-ng], [https://github.com/espeak-ng/espeak-ng])
+AC_INIT([eSpeak NG], [1.51-dev], [https://github.com/espeak-ng/espeak-ng/issues], [espeak-ng], [https://github.com/espeak-ng/espeak-ng])
 AM_INIT_AUTOMAKE()
 LT_INIT
 
diff --git a/src/windows/config.h b/src/windows/config.h
index a257f6da..937b67ed 100644
--- a/src/windows/config.h
+++ b/src/windows/config.h
@@ -9,4 +9,4 @@
 #define _CRT_NONSTDC_NO_DEPRECATE
 
 // This is created by autoconf on POSIX-compatibe build environments.
-#define PACKAGE_VERSION "1.50"
+#define PACKAGE_VERSION "1.51-dev"