[GNC] Upgrading GnuCash

[Fred Bone]

Currently running 2.6.21 (without issues) and think I should probably
upgrade to 4.whatever.
I know I need to bridge via 3.something, but can I safely assume that
3.11 will do the necessary data tweaking, or should I start with an
earlier 3.x? And is opening and closing my files sufficient, or do I
need to take any other actions before further upgrading to 4?
I've looked on the website and the wiki for answers but failed to find them.
TIA ... F