I think we need an alert on opening obsolete projects even in case of minor version changes.

I apologize if this topic has already been covered, I’m writing in a rush.
In my dev rig quietly sit:
Unity 3.7, Unity 4.0, Unity 5.0, Unity 5.2, Unity 5.2.3, Unity 5.3.1 and Unity 5.3.2
(not yet installed 5.3.4 and 5.4 beta)
Nearly each version is needed to open a particular project, even the old ones.
We all know why… recompiling paranoia.
I am scared to death before opening old stuff not in the recent projects pane.
My fingers shake, I sweat, need a glass of water, go to the tolilet, go back to the PC, stare to the screen and so on.
Last night I lost nearly three hours because I opened by mistake a 5.2.3 project with 5.3.2. After a lifetime in recompiling, debugger was full of rubbish I had to manually sort out.
So I suggest that unity version label must be saved within the project, and an alert should pop up on opening obsolete files even in case of minor version changes.
Something like: “This project was created in unity X.x.x. are you shure you want to proceed and upgrade it?
Do you think it can be a good idea?

There is a pop-up when you try to open a Unity project that used a different version of Unity. Do you not get this pop-up?

Example:

UH! this is exactly what I’ve been looking for but I’ve never seen this pop-up. Is it a new feature to 5.3.4 or this check must be enabled somewhere?

Oh! We’ve had this for a while now, it’s super strange that you don’t get the pop up. I don’t think you can even disable this check, should be there by default and mandatory for everyone.

I can confirm this pop-up never…pops up. I’ve just opened several old test projects with 5.3.2 and the first thing that appears is “hold on, compiling scripts”
However, the usual “project upgrade required” pop up appears if I open a Unity4 project with Unity5, It is absolutely not the pop up you posted as an example.
SaraCecilia, could you please check by opening your old project with 5.3.2, just to be sure?