diff --git a/configure.ac b/configure.ac
index 3bf23299c..19a0a3a03 100644
--- a/configure.ac
+++ b/configure.ac
@@ -118,7 +118,7 @@ LT_INIT([shared static])
 
 LT_NGSPICE_CURRENT=0
 LT_NGSPICE_REVISION=5
-LT_NGSPICE_AGE=0
+LT_NGSPICE_AGE=1
 LIBNGSPICE_SO_VERSION=$LT_NGSPICE_CURRENT.$LT_NGSPICE_REVISION.$LT_NGSPICE_AGE
 
 # Announce the libtool version