Bump ABI version for new release
diff --git a/src/nn.h b/src/nn.h
index a0b6a08..c462175 100644
--- a/src/nn.h
+++ b/src/nn.h
@@ -66,7 +66,7 @@
 #define NN_VERSION_CURRENT 2
 
 /*  The latest revision of the current interface. */
-#define NN_VERSION_REVISION 0
+#define NN_VERSION_REVISION 1
 
 /*  How many past interface versions are still supported. */
 #define NN_VERSION_AGE 2