Hello Dejan,

you may be right, it seems there's a misalignment between Javascript and iOS clients, where the Javascript client omits the user for a null parameter, while the iOS client sends an empty user for a nil parameter. Thanks for reporting it.

We will fix this bug in an upcoming version. As suggested above, consider upgrading to Server 6.x, as this fix may not be released for older client libraries.

Best regards,

Gianluca