>I am going to have to upgrade a project I look after from 7 to 9 - are there any things to look out for out of the starting gate, or ought it just be a recompile, and all is good? Many thanks for your input!

Basically recompile, yes. Be prepared for some errors, possibly more than you hoped for, but don't worry. VFP9 is much less forgiving about syntax errors, typically missing a sign here and there, but you will get relatively good error messages. Also expect to get a few SQL errors, read Set EngineBehavior in Help for an explanation. Beware that these errors need to get fixed, since the old syntax, which isn't accepted anymore, could give you wrong results. So these changes were for very good reasons.

Before starting the recompilation, I suggest that you read What's new in Help. Sergey's blog is also really good. https://www.berezniker.com/content/pages/visual-foxpro/moving-applications-vfp-90