diff --git a/module/nyacc/README.nyacc b/module/nyacc/README.nyacc
index 314cdb3c..69c5c1d2 100644
--- a/module/nyacc/README.nyacc
+++ b/module/nyacc/README.nyacc
@@ -1,4 +1,4 @@
-This is a version 0.75.5 of NYACC (Not Yet Another Compiler Compiler!).
+This is a version 0.75.5+c99dev of NYACC (Not Yet Another Compiler Compiler!).
 
 Copyright (C) 2015-2017 Matthew R. Wette
 
diff --git a/module/nyacc/lalr.scm b/module/nyacc/lalr.scm
index 1ec73994..b30ba45b 100644
--- a/module/nyacc/lalr.scm
+++ b/module/nyacc/lalr.scm
@@ -50,7 +50,7 @@
   #:use-module (nyacc util)
   )
 
-(define *nyacc-version* "0.75.5")
+(define *nyacc-version* "0.75.5+c99dev")
 
 
 ;; @deffn proxy-? sym rhs