tacitly revised hardware ;-)

Meanwhile, I have purchased the devices 4-5. So why just only give feedback at the 5th?
Quite simply, AVM has incorporated customer feedback to the first version to a second version obviously.
Now that's a reason this is emphasized here too positive.

Positives:
+ Is better in the hand.
+ The lower part (approximately from battery) has become a little more difficult. The overthrow of an older MT-F is our top of the housing broken something, because it was not strong enough in the charging cradle. That should not happen now.
+ Battery Charger can fully charge. For older devices, the battery is often held only 1 call long, but the power itself was okay. In a AVM C4 of the battery is fully recharged. This apparently is the new MT-F is no longer necessary, possibly also because it is fixed in the charging cradle (by weight gain) and thus has permanent contact with the charger.
+ No more creaking.
+ The battery is firmly in place

Negatives
- I can not think right now of anything.