Time for the annual Travis Erlang version hunt

Why is there no list of supported Erlang versions on Travis?!
diff --git a/.travis.yml b/.travis.yml
index ba68c7e..3cbdba2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,10 +3,10 @@
   email:
     - hello@alind.io
 otp_release:
-  - 18.2.1
+  - 18.2
   - 17.5
   - R16B03-1
-  - R15B03-1
+  - R15B03
 before_script: "make get-deps"
 script: "make test"