I'm having trouble updating our office D715s.
I'm on snom715-SIP version 10.1.37.11. By loading the correct link found in the service hub on the SNOM website on the fw update page (example http://downloads.snom.com/fw/10.1.39.11/bin/snom715-10.1.39.11-SIP-r.bin) I receive this error from the phone (photo attached).

Trying with an even newer version I get the same error. Tested with two different phones.