If you are already using mIRC, the mIRC installer will upgrade your current version of mIRC to the latest version and will keep your existing settings.
If your settings are no longer there after upgrading, the most common reason is that you are using anti-virus software that incorrectly thought the new version of mIRC was a trojan/virus and deleted your settings without telling you.
The mIRC installer backs up any existing settings to a "backups" folder in your mIRC folder, so you may still be able to retrieve them, unless the anti-virus software deleted those as well. If you find your settings in your "backups" folder, you can simply copy them back to the main mIRC folder and mIRC will use them.
