diff --git a/libphobos/configure b/libphobos/configure
index 9a59bad34acc3344122552e54f5eaa92b153b713..9b6a41879d36540149dfacb8d5d8c574c5e86e12 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 bce8538861278d116d4c812b82ff9d3fde623516..ab82eacc204aed6e349f03716dc41e27490fdafa 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!)