Upgrading a really old version of SEF

When our site was being developed we used a very old version of SEF Advance, i think it was 4.2.2, purchased from another client.

I heard the latest version is 6.x for Joomla 1.0x. One of the issues we are facing with 4.2.2 is that when we switch over to a hyphen (-) from an underscore (_) content does not "auto-redirect" to the updated version.

For instance if a banner was linked to /news_1_1_2/ when we switch to a hyphen the link does not try to find the new version (or layout).

I am going to assume that a later version of SEF Advance for J1.0x is going to help solve this, but I am not sure how to go about upgrading such an old version.

I am not sure whether you need to switch off SEF/SEO in configuration, then uninstall SEF Advance and simply re-install the latest version?

Thanks for your help.

No, neither version of SEF Advance does such redirect. It's important to choose your settings in the beginning. Switching it later can only harm your PR.

To upgrade old version of SEF Advance you must uninstall the old and reinstall, doing the settings again.