Please provide the fatal error message. This is not 4.9 compatibility issue. Something is irregular with your PHP, some extensions are not enabled or ...

Thank you for letting us know. We'll check this.

I'm sorry but I have no clue, this code works on dozens of websites without any issue, something is irregular on your website. Try to put it in the pa...

The last two are not wpForo fields. Some plugin tries to add their fields in wpForo register form through hooks. Please deactivate all plugins, delete...

Please navigate to Dashboard > Settings > Forums > Styles admin page, put this CSS code in Custom CSS Code textarea, save, delete all caches ...

Forum URL please

Thank you for letting us know. We've fixed these phrases in next 1.4.3 version. It'll be released very soon. In any case if you need this urgently ple...

It seems you insert the code in non-php area. please leave some screenshot of your functions.php with the inserted code.

I'm sorry but this is not included in near upcoming versions. There is an alternative way to move posts described here:

Try to change it in all front-end phrases. Navigate to Dashboard > Forums > Phrases admin page, search for "topic" word and change the phrase va...

I'm sorry but there is no way. We'll take this under consideration for future releases.

I'm sorry but there is no way. It has own Attachment Manager page in Dashboard under the Media Library menu and under the Forums menu. For farther sup...

You should ask your hosting service support to restore your database or at lease send the backup database file. I'm really sorry but there is no other...

The wrappers are different, so the tree of CSS classes are different too, they can't be identical. The wpForo sidebar is an extra sidebar loaded in pa...

Yes, you're right it's not compatible yet. I'll let them know.