upgrade guide for 4.1.1

Author: dandelany

docs/upgrade-guides/4-1-0-to-4-1-1.md

@@ -1,4 +1,7 @@
 # 4.1.0 to 4.1.1
 
-This document describes the upgrade instructions from `4.1.0` to `4.1.1`.
+No special upgrade instructions are necessary for PlanDev.
 
+### SeqDev: SeqN language improvements
+
+For SeqDev users, this release includes a new release of the [aerie-sequence-languages](https://github.com/NASA-AMMOS/aerie-sequence-languages) library ([**v1.0.2**](https://github.com/NASA-AMMOS/aerie-sequence-languages/releases/tag/v1.0.2)) with fixes for known issues. Users with **custom sequencing adaptations** should update this library and rebuild/reupload their adaptation.