diff --git a/README.md b/README.md
index 4e0ff54..cd3a6b8 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 GammaLib information
 ====================
-* Version: 1.4.0 (12 August 2016)
+* Version: 1.5.0.dev1 (12 August 2016)
 * Author:  Juergen Knoedlseder (jurgen.knodlseder@irap.omp.eu)
 
 [![Build Status](https://cta-jenkins.irap.omp.eu/buildStatus/icon?job=gammalib-integrate-os)](https://cta-jenkins.irap.omp.eu/job/gammalib-integrate-os/)
@@ -184,7 +184,7 @@ If everything works successfully you should see
 or
 
     ============================================================================
-    Testsuite summary for gammalib 1.4.0
+    Testsuite summary for gammalib 1.5.0.dev1
     ============================================================================
     # TOTAL: 21
     # PASS:  21
diff --git a/configure.ac b/configure.ac
index 7657963..cb8d76c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -29,7 +29,7 @@
 #############################################################################
 # Initialisation                                                            #
 #############################################################################
-AC_INIT([gammalib], [1.4.0], [jurgen.knodlseder@irap.omp.eu], [gammalib])
+AC_INIT([gammalib], [1.5.0.dev1], [jurgen.knodlseder@irap.omp.eu], [gammalib])
 AC_CONFIG_SRCDIR([src/support/GTools.cpp])
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_AUX_DIR([.])
diff --git a/doc/Doxyfile b/doc/Doxyfile
index a979c78..743ee41 100644
--- a/doc/Doxyfile
+++ b/doc/Doxyfile
@@ -32,7 +32,7 @@ PROJECT_NAME           = GammaLib
 # This could be handy for archiving the generated documentation or
 # if some version control system is used.
 
-PROJECT_NUMBER         = 1.4.0
+PROJECT_NUMBER         = 1.5.0.dev1
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer
diff --git a/doc/source/conf.py b/doc/source/conf.py
index 3986edf..0c0a770 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -55,10 +55,10 @@ copyright = u'2006-2016, GammaLib developers'
 # built documents.
 #
 # The short X.Y version.
-version = '1.4'
+version = '1.5'
 
 # The full version, including alpha/beta/rc tags.
-release = '1.4.0'
+release = '1.5.0.dev1'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
diff --git a/gammalib.pc.in b/gammalib.pc.in
index 7db91ac..0987b62 100644
--- a/gammalib.pc.in
+++ b/gammalib.pc.in
@@ -6,7 +6,7 @@ includedir=${prefix}/include
 Name: GammaLib
 Description: Versatile toolbox for analysis of astronomical gamma-ray data
 URL: http://cta.irap.omp.eu/gammalib/
-Version: 1.4.0
+Version: 1.5.0.dev1
 Requires: 
 Requires.private: @CFITSIO@
 Conflicts: 
diff --git a/sonar-project.properties b/sonar-project.properties
index a861360..fee53c2 100644
--- a/sonar-project.properties
+++ b/sonar-project.properties
@@ -1,7 +1,7 @@
 # Required metadata
 sonar.projectKey=gammalib
 sonar.projectName=GammaLib
-sonar.projectVersion=1.4.0
+sonar.projectVersion=1.5.0.dev1
 
 # Description
 sonar.projectDescription="Versatile toolbox for scientific analysis of astronomical gamma-ray data"