Tough decision. In the related Poll, I would say migrate and protect what data currently exists even if that means implementing technology that the current AmigaOS software cannot correctly handle.
The forums are most popular, I presume, so choose a new CMS platform that would be easiest in data migration from Xoops to it.
It is unfortunate that the site and AmigaOS software will not be compatible, but it seems that either the site dies or an upgrade is needed. If the Site cannot be ported to another Hosting provider with the currently utilized PHP version, then make the upgrade.
Good luck whatever you decide.
