Hi @123456jk
I hope you’re well today!
It’s a fair question but I cannot promise full compatibility with 4.9. We are doing our best to provide as much backwards compatibility (both in terms of WordPress versions and PHP versions) as possible but that’s quite “far away” and even if it does activate without issues, I can’t promise that all the features will work and work correctly. I’m afraid we wouldn’t be able to help in case of troubles with such setup.
It’s not only a matter of compatibility with WordPress core also but PHP version and actually other plugins on site as well.
Having said that, I tested it on basic 4.9 install with PHP 7.4 and it does install and activate but some parts of the plugin seem to be throwing errors, I’m afraid so I would expect more such issues.
The best I can can suggest in this case would be for you to set up a copy (exact “one to one” copy) of the site as a staging/test site and test the plugin there – this way you could safely check if it would work for you but if possible, it would be much better to update everything including WordPress instead.
Kind regards,
Adam