scim-avro has been replaced by ibus-avro, and that too pretty successfully. Bangla users on GNU/Linux can now install ibus-avro from the ibus-avro GitHub repo.
The present version supports intelligent word guessing as you type, one of the features that I missed on scim-avro. It works across LibreOffice/OpenOffice, Firefox and text editor, thanks to the stability of iBus.
Overall, a big round of congratulations to the Avro team for this lovely piece of work.
For details, check iBus page at OmicronLab.
Image source: http://github.com/sarim/ibus-avro used under the Mozilla Public License 1.1.