Hi Andreas,
That's totally correct but my only concern is that there is no such guide line from SAP to use 1.6 for WCEM client.
I know if we go to higher version then it always support depreciated methods/libraries as well but sometime it becomes very difficult to convince customer.
If you get a chance where you have o raise an OSS Message then again SAP asks what was recommended.
By keeping above queries in mind I think Patrick needs a SAP written document otherwise as a technical person there is no second thought to use 1.6 as NW 7.4 is itself using 1.6.
Thanks,
Hamendra