Hi Alex,
...I am unsure as to whether the licence file is actually the executable (/opt/sqlanywhere16/bin64/dbsrv16) or something else!
It's "something else". 
There should be a companion dbsrv16.lic file to the dbsrv16 binary in the bin64 directory:
hostname:/opt/sqlanywhere16/bin64$ ls dbsrv16*
dbsrv16 dbsrv16.lic
This is the file that is targetted by the Server Licensing Utility (dblic).
Jeff Albion
SAP Active Global Support