There's been a few major and poorly documented changes in functions and script step for Custom Web Publishing (CWP) in FileMaker Server 16.
One is CWP no longer has access to Get ( TemporaryPath ) and Get ( DocumentsPath )*.
Another is that CWP is is no longer able to use Send Mail to send attachments.
These changes were not in release notes and only discovered in a testing environment and following up with the FM 16 help file.
I suspect there may be other changes, but I'm not prepared to read through every function and script step to compare 15 and 16.
My idea is to restore the ability of CWP to use the steps and functions that were accessible in FM 15.
*According to the Help file, Get ( DocumentsPath ) was incompatible with CWP in FM 14.