Just to lend some insight into the confusion, the latest stuff in 5E isn't officially powered based on the description. However, based on the accompanying artwork, anything that bulky(especially the medium and heavy versions) would have to have some sort of motion-assisted servos just in order for the wearer to move. So it's not really powered armour like Iron Man or 40K, where it allows you to punch through walls and such. In fact, because it slows down your movement speed, I'd argue it is only partially powered, and the technology behind the joints and mobility is lagging a bit behind.
Interestingly, in 4E the Milspec armour COULD be powered. There were 2 Milspec-only armour modifications that were pertty expensive, but added 1-3 extra points of strength(that stacked with the user's augmented strength), and extra leg servos that added to the user's run speed. Both of those combined basically scream Power Armour, so I'm not sure why the designers and writers decided to remove it for 5E. Maybe they thought it was getting a bit too sci-fi for Shadowrun, and didn't fit with the whole Future Dystopia atmosphere.