Hello,
These are "warnings" and not fatal errors.
The plugin will work find in a production environnement (since PHP messages should not be displayed to the end-user otherwise it would be a security issue).
But it means that it might be a problem with PHP 8.2 when the warning becomes an error.
We will update the plugin.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.