Oh, btw:
In addition, with a new promise of a soon to be coming new major release 7.6, why would we invest in having the site updated to 7.57 instead of waiting for 7.6 which is entering beta? But then version 8.0 was promised for many years in the same way.
It'll make your upgrade far easier (and potentially cheaper). You'll have to be running a current copy of threads to import, so whoever does your upgrade would have the hurtle with upgrading to 7.3 then again to 7.5.7 then to the new version (v7.3's upgrade commonly fails out and is a pain to work with)