diff --git a/configure.ac b/configure.ac
index 0c0508a3..69a12b0e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -22,7 +22,7 @@
 AC_PREREQ([2.63])
 AC_INIT(
   [FRE NCTools],
-  [2026.01],
+  [2026.01-dev],
   [https://github.com/NOAA-GFDL/FRE-NCtools/issues],
   [fre-nctools],
   [https://github.com/NOAA-GFDL/FRE-NCtools])