Upgrades for your sub

Hello everybody,

I have been playing this game for a while now and i have to say that apart from the occasional problems with DRM, i actually like it.

Now i was wondering if somebody knows if there is a list with all the upgrades for your submarine and when they become available to buy.

I have been looking for this but haven't found it yet. I can remember from SHIII that there was a list where you could see that for example a certain hydrophone upgrade became available on september 1942. So, does anyone know if something like this is available for SHV? Please let me know.