Champion unlocks not making sense

[Misery]

Okay, this question is quick:

Levelled up my champion just now, mostly been using the Spire type.  Had those photon ray things, forget the exact name, specifically the level 3 versions.  Go into champion unlocks, I unlock the level 4 versions.  Apply, save.

Go into design.... and hey, I've still got the level 3 versions there when I look at the current design.  I figure, okay, I have to replace these in the design manually.  Click to select new ones.... level 3.   Okay, I'll just delete the design and redo it..... level 3.  Blow up the blasted ship so it resets at home base, and THEN do it..... level 3.  Each time, I check the unlock screen to see that it is, indeed, UNLOCKED at level 4, which it is, but everything else seems to be utterly ignoring this fact. 

So.... what might I be missing there?  I'm hoping I didn't just waste unlock points on something unusable considering how long those nebula missions take... I at least saved beforehand though.

[WingedKagouti]

You need a bigger ship to equip the higher level guns. It's one of those things that would be nice to have clearly displayed somewhere, like "This ship can equip up to level 3 guns, get a bigger ship to equip higher level guns" or something similar.

[TheVampire100]

You need a bigger ship to equip the higher level guns. It's one of those things that would be nice to have clearly displayed somewhere, like "This ship can equip up to level 3 guns, get a bigger ship to equip higher level guns" or something similar.

Little thing to add: Your ship gets bigger when you reach a certain level. i don't know the exact level anymore but I think it was 10?
Somewhere it is actually displayed. It says somewhere (can only equip level X equipment).
I will check this to be sure, just give  me  a minute.

EDIT: I was right. When you hover over your champion it states "can only mount modules of Mk X or lower".

[Bognor]

Mark IV modules require a cruiser hull, which will be unlocked when you complete your 5th nebula.

I guess there might be times you want to unlock a module your champion can't yet use for the sake of a modular fort.

[motai]

note modular forts only use level 3 max equipment (subject to change in patches without notice)