diff --git a/configure.ac b/configure.ac
index d99793e3..73f48b57 100644
--- a/configure.ac
+++ b/configure.ac
@@ -69,7 +69,7 @@ AC_DEFINE([HAVE_PTHREADS],1,
 dnl libtool versioning for libqalculate
 
 dnl increment if the interface has additions, changes, removals.
-QALCULATE_CURRENT=43
+QALCULATE_CURRENT=23
 
 dnl increment any time the source changes; set to 
 dnl  0 if you increment CURRENT
@@ -78,7 +78,7 @@ QALCULATE_REVISION=0
 dnl increment if any interfaces have been added; set to 0
 dnl  if any interfaces have been removed. removal has 
 dnl  precedence over adding, so set to 0 if both happened.
-QALCULATE_AGE=21
+QALCULATE_AGE=0
 
 AC_SUBST(QALCULATE_CURRENT)
 AC_SUBST(QALCULATE_REVISION)