diff --git a/doxygen.cfg b/doxygen.cfg
index ab4eec20..a0ad3176 100644
--- a/doxygen.cfg
+++ b/doxygen.cfg
@@ -31,7 +31,7 @@ PROJECT_NAME           = "Intel SPMD Program Compiler"
 # This could be handy for archiving the generated documentation or
 # if some version control system is used.
 
-PROJECT_NUMBER         = 1.5.0
+PROJECT_NUMBER         = 1.5.1dev
 
 # The OUTPUT_DIRECTORY tag is used to specify the (relative or absolute)
 # base path where the generated documentation will be put.
diff --git a/ispc.h b/ispc.h
index 4b7ae732..82cb9050 100644
--- a/ispc.h
+++ b/ispc.h
@@ -38,7 +38,7 @@
 #ifndef ISPC_H
 #define ISPC_H
 
-#define ISPC_VERSION "1.5.0"
+#define ISPC_VERSION "1.5.1dev"
 
 #if !defined(LLVM_3_1) && !defined(LLVM_3_2) && !defined(LLVM_3_3) && !defined(LLVM_3_4)
 #error "Only LLVM 3.1, 3.2, 3.3 and the 3.4 development branch are supported"