diff --git a/src/libiso8601/soversion b/src/libiso8601/soversion
index 3d77ea3..5c622af 100644
--- a/src/libiso8601/soversion
+++ b/src/libiso8601/soversion
@@ -12,4 +12,4 @@
 SOMAJOR=1
 
 # SOMICRO is bumped every time there is a binary-compatible release.
-SOMICRO=3
+SOMICRO=4