[Roger Labroue]

Good question.

According to Adobe, v4.1 is included with v4.2.
Source: https://www.adobe.com/products/premiere/pdfs/premiere_pro_4_2_update.pdf

However, as per the size of the updates, I suspect v4.0.1 not to be included in v4.1, nor in v4.2. I will therefore wait for any confirmation before beginning on the installations.

Yours,
Labroue