The JIRA for support of DB2 10.5 is CON-15703.
I was told on Monday of this week (April 4th) that supporting 10.5 has finally been re-prioritized for development.
The log format changes between 10.1 and 10.5 are very minor (a few extra columns) so I'm hoping that we will see this supported in one of the next two SmartConnector releases. No promises of course but if you (and any other customers) waiting for 10.5 support also open a ticket and reference the above JIRA, the priority for getting this supported will increase further.
Having said that, my DB2 DBAs just told me that 11.0 will be released soon so we are going to be starting this process all over again really soon to get the latest version supported! At least for the next one, I will be opening the JIRA for DB2 11.0 as soon as I have a spinning copy of this version in my environment.