If you upgraded via FTP I suspect you may have missed the step where you upgrade the .web file.
Log in and delete all .web files (del *.web). S/FTP all the .web files, there should be just one (wr11.web).
Then reboot.
If that fails, you could try flashwriter using the ethernet method but this has risk.
https://www.digi.com/support/productdetail?pid=5644&type=firmware
https://ftp1.digi.com/support/firmware/using_flashwriter.pdf
Nicholas Wilson
Your IoT
https://www.YourIoT.com.au