diff --git a/VERSION b/VERSION
index 867e524..cb842bc 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.2.0
\ No newline at end of file
+1.3.0-dev
\ No newline at end of file
diff --git a/src/gen_smtp.app.src b/src/gen_smtp.app.src
index 62232b8..db29bcb 100644
--- a/src/gen_smtp.app.src
+++ b/src/gen_smtp.app.src
@@ -1,6 +1,6 @@
 {application, gen_smtp, [
     {description, "The extensible Erlang SMTP client and server library."},
-    {vsn, "1.2.0"},
+    {vsn, "1.3.0-dev"},
     {applications, [kernel, stdlib, crypto, asn1, public_key, ssl, ranch]},
     {registered, []},
     {licenses, ["BSD-2-Clause"]},