Hello.
I do:

1. Download zip of codoforum 5.2.1
2. Upload to server and unzip
3. Setting up Nginx. I give to codoforum php-fpm 8.2.
4. Then i'm install from browser this engine.

In result i got PHP errors.

Deprecated: Creation of dynamic property CODOF\Asset\Stream::$parser is deprecated in /home/site/hub/sys/CODOF/Asset/Stream.php on line 98
Deprecated: Creation of dynamic property CODOF\Plugin::$db is deprecated in /home/site/hub/sys/CODOF/Plugin.php on line 16
Deprecated: Creation of dynamic property CODOF\Smarty\Single::$parent is deprecated in /home/site/hub/sys/CODOF/Smarty/Single.php on line 19
Deprecated: Creation of dynamic property CODOF\User\RememberMe::$db is deprecated in /home/site/hub/sys/CODOF/User/RememberMe.php on line 13
Deprecated: mb_convert_encoding(): Handling HTML entities via mbstring is deprecated; use htmlspecialchars, htmlentities, or mb_encode_numericentity/mb_decode_numericentity instead in /home/site/hub/sys/CODOF/Format.php on line 26
Deprecated: Creation of dynamic property Controller\forum::$view is deprecated in /home/site/hub/sys/Controller/forum.php on line 383
Deprecated: Creation of dynamic property CODOF\Asset\Stream::$parser is deprecated in /home/site/hub/sys/CODOF/Asset/Stream.php on line 98
Deprecated: Creation of dynamic property CODOF\Asset\Stream::$parser is deprecated in /home/site/hub/sys/CODOF/Asset/Stream.php on line 98
Deprecated: Creation of dynamic property CODOF\Asset\Stream::$prependURL is deprecated in /home/site/hub/sys/CODOF/Asset/Stream.php on line 166
Deprecated: Creation of dynamic property Smarty_Internal_Template::$compiled is deprecated in /home/site/hub/sys/vendor/smarty/smarty/libs/sysplugins/smarty_internal_template.php on line 719
Deprecated: Creation of dynamic property Smarty_Internal_Template::$compiled is deprecated in /home/site/hub/sys/vendor/smarty/smarty/libs/sysplugins/smarty_internal_template.php on line 719

Then i tried to give him php 5.6 and 7.4. Errors not gone.
Then i give him back 8.2.
I use CloudFlare with Auto Minify, Brotli and Early Hints.
In my example on my site, Codoforum loose all CSS tamplates.

Link to my site (NO SPAM, NO AD) (It's just for get more info about a problem)
or1k.net/hub

@admin

Try to set your website to use php 8.1.18 . This fixed these errors for me.

Encountered PHP errors while installing Codoforum 5.2.1 on the server with Nginx and PHP-FPM 8.2. Ensure compatibility between Codoforum and PHP-FPM versions, similar to using a Phone Case that fits the phone model properly to avoid issues.