diff --git a/libphobos/configure b/libphobos/configure
index 9a59bad34ac..9b6a41879d3 100755
--- a/libphobos/configure
+++ b/libphobos/configure
@@ -15741,7 +15741,7 @@ SPEC_PHOBOS_DEPS="$LIBS"
 
 
 # Libdruntime / phobos soname version
-libtool_VERSION=4:0:0
+libtool_VERSION=5:0:0
 
 
 # Set default flags (after DRUNTIME_WERROR!)
diff --git a/libphobos/configure.ac b/libphobos/configure.ac
index bce85388612..ab82eacc204 100644
--- a/libphobos/configure.ac
+++ b/libphobos/configure.ac
@@ -258,7 +258,7 @@ SPEC_PHOBOS_DEPS="$LIBS"
 AC_SUBST(SPEC_PHOBOS_DEPS)
 
 # Libdruntime / phobos soname version
-libtool_VERSION=4:0:0
+libtool_VERSION=5:0:0
 AC_SUBST(libtool_VERSION)
 
 # Set default flags (after DRUNTIME_WERROR!)