Hi @pbparjeter - I’m sorry but I don’t have the knowledge to answer your question. Hopefully someone else can help you.
But here’s a link to the list of bug fixes. You might be able to see if these changes are likely to change your use of Twine 1.4:
I’m not sure if this list is complete.
One change that I’ve found that doesn’t seem to be in the list is:
“Changed the default value of the startAt parameter of testBuild() to ‘Start’, so the test play string replacement (“START_AT”) will always have a value during test plays. Story formats may use this to detect a test play and enable any test/debug mode they may have.”
I’m now sure that the bug fix list that I linked to in my last post is NOT complete. The bug list was made 8 years ago, but since then 9 files in the source code have been changed. Best to go to github and open the comments on each file that was changed 7 or 6 years ago - there is usually a description of the changes made.