Version 6.1.9 works fine on my site (Joomla 3.10.12 PHP 7.4.33)
I tried 6.1.12 on a test site (xampp, Joomla 5.0.2 PHP 8.2.4 MariaDB 10.4.28). The backward compatibility plugin is enabled.
Deprecated: Creation of dynamic property CompojoomInstaller::$type is deprecated in C:\xampp\htdocs\25jtx.ru\tmp\install_65b635eaa6e0d\libraries\compojoom\libraries\compojoom\installer\installer.php on line 53
Deprecated: Creation of dynamic property CompojoomInstaller::$parent is deprecated in C:\xampp\htdocs\25jtx.ru\tmp\install_65b635eaa6e0d\libraries\compojoom\libraries\compojoom\installer\installer.php on line 54
Deprecated: Creation of dynamic property Com_CommentInstallerScript::$installer is deprecated in C:\xampp\htdocs\25jtx.ru\tmp\install_65b635eaa6e0d\script.php on line 155
Deprecated: Creation of dynamic property Com_CommentInstallerScript::$status is deprecated in C:\xampp\htdocs\25jtx.ru\tmp\install_65b635eaa6e0d\script.php on line 228
Deprecated: Creation of dynamic property CompojoomUtilsComponent::$config is deprecated in C:\xampp\htdocs\25jtx.ru\libraries\compojoom\utils\component.php on line 31
Comment configuration for com_content on tab Template (default) see screenshot:
Deprecated: Creation of dynamic property Joomla\Registry\Registry::$id is deprecated in C:\xampp\htdocs\25jtx.ru\libraries\vendor\joomla\registry\src\Registry.php on line 937
Deprecated: Creation of dynamic property Joomla\Registry\Registry::$component is deprecated in C:\xampp\htdocs\25jtx.ru\libraries\vendor\joomla\registry\src\Registry.php on line 937
and other messages.
It looks like the code has not yet been adapted to PHP 8.2.4 and higher. Will you adapt CComment to Joomla 5? The best free extension for comments.
Sincerely, Alexander