Register String in single quotes gives Fatal Error, cannot add trunks

I was fiddling trying to get registration string correct for my SIP provider and I ran into this problem.

A Google search revealed someone else with exactly the problem. The solution was to upgrade the FreePBX, however my version is far past the version suggested by this post.

Any advice on how to get past this is appreciated.

My FreePBX version is

I don’t see any corresponding FreePBX bug related to this.

If you can create a bug report someone can try to reproduce and resolve this.