May I add a permanent stroke to an excisting font?

Hi everyone

Regarding strokes on fonts:

My company use the font Didot for our marketing materials. But it has very thin serifs/lines and is hard to read in smaller font sizes some times. Therefore we often put strokes on the letters. But it's a hazzel to do often, and is not always good on print...

So we've found a graphic designer who can put a "permanent" stroke on it for us, and install this to use for materials where the original font is too thin (so we may supply with this new version). Is this ok to do, in terms of licencing??

We have no intentin of reselling the new font or alternating the original - we just want a thicker stroke on some letters to make the text more readable.

Thanks in advance!