Stambia DI Designer 2021 (S20.4.0) and Stambia DI Runtime 2021 (S20.4.0) are available at download.
They both feature a list of improvements and fixed issues which can be found in the changelogs.
The release notes can be found here: Designer release note, Runtime release note
The changelogs here: Designer changelog, Runtime changelog
And the download pages here: Designer download, Runtime download