diff --git a/configure.ac b/configure.ac
index 393fc278d..63fff48e4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-AC_INIT([primesieve], [5.5.0], [kim.walisch@gmail.com])
+AC_INIT([primesieve], [5.5.0-rc1], [kim.walisch@gmail.com])
 AC_SUBST([primesieve_lib_version], [5:0:0])
 
 AC_PREREQ([2.62])
diff --git a/doxygen/Doxyfile b/doxygen/Doxyfile
index fd7de06e4..1a2dcb992 100644
--- a/doxygen/Doxyfile
+++ b/doxygen/Doxyfile
@@ -1,5 +1,5 @@
 PROJECT_NAME           = "primesieve"
-PROJECT_NUMBER         = 5.5.0
+PROJECT_NUMBER         = 5.5.0-rc1
 INPUT                  = mainpage.dox \
                          ../include/primesieve.hpp \
                          ../include/primesieve.h \
diff --git a/include/primesieve.h b/include/primesieve.h
index 994f7586d..f857157c3 100644
--- a/include/primesieve.h
+++ b/include/primesieve.h
@@ -14,7 +14,7 @@
 #ifndef PRIMESIEVE_H
 #define PRIMESIEVE_H
 
-#define PRIMESIEVE_VERSION "5.5.0"
+#define PRIMESIEVE_VERSION "5.5.0-rc1"
 #define PRIMESIEVE_VERSION_MAJOR 5
 #define PRIMESIEVE_VERSION_MINOR 5
 #define PRIMESIEVE_VERSION_PATCH 0
diff --git a/include/primesieve.hpp b/include/primesieve.hpp
index 5c73d131d..9665f3428 100644
--- a/include/primesieve.hpp
+++ b/include/primesieve.hpp
@@ -15,7 +15,7 @@
 #ifndef PRIMESIEVE_HPP
 #define PRIMESIEVE_HPP
 
-#define PRIMESIEVE_VERSION "5.5.0"
+#define PRIMESIEVE_VERSION "5.5.0-rc1"
 #define PRIMESIEVE_VERSION_MAJOR 5
 #define PRIMESIEVE_VERSION_MINOR 5
 #define PRIMESIEVE_VERSION_PATCH 0