[development] 5.x to 6.x migration timeline, best practices, tips

[Fred Jones]

> and one monster custom module (~ 7000 lines), and I'm looking at migrating
> to 6.x sometime in the next few months.

7K? Wow.

> So I was wondering if anyone had any suggestions on things to look out for
> or a generalized timeline?  My guess was at least 100 hours to upgrade to
> 5.18, migrate to 6.12, test the system, and then adjust the theme and api
> calls.

It's a very tough call when you consider that you have 7K lines of
code that you aren't familiar with it. One note I can share is that
you definitely must examine each contrib module's upgrade
instructions--many *require* that you first upgrade them to the
latest/last 5.x version before moving to 6. And they mean it. ;)

Good luck.