Question regarding type XXI and Rub 1.43

[misterpinna]

From the RuB 1.43 README:

The Type XXI: only 11th Flotilla got the Type XXI operational before the war's end. This mod makes only very small concessions to playability in this regard - if you want to command a Type XXI, you will have to transfer to one between the beginning of July and mid-August 1944. You will then spend a frustrating few months as your new boat undergoes delay after delay. You will finally get your new boat between March and May 1945 - if you're lucky you will have enough time left to do a patrol in it before the war ends.

This means that the mod team made something to the config files to delay the type XXI release, right? Now I am in autumn 1943, with a type IX, and I would like to have the chance to try the type XXI in the early 1944 (as the original settings permitted, afair). Is it possible, using RuB 1.43 (I like it very much) to have the type XXI in april '44?

Thanks in advance for the replies