A German court issued a sales ban on the iPhone 7, iPhone 8 and their respective Plus models for infringing on a Qualcomm Envelope tracking patent. To get around this, Apple has informed local stores that its building new units, which will be available in about four weeks.
The court ruled that iPhones sold in Germany, which use chips supplied by Intel and Qorvo, infringe on Qualcomm patents. Apple will source different chips to get around this issue.
The US also found that Intel chips infringe on a Qualcomm patent, but refused to ban them (saying it would hamper competition). Interestingly, Qorvo chips are in the clear as far as US regulators are concerned. A Chinese court also issued a ban, but Apple is still appealing that decision.
Anyway, the only phones currently available on Apples German site are the iPhone XS, XS Maxand XR. The iPhone 7 and 8 models remain available in China.
PS. Envelope tracking dynamically changes the power sent to a radio amplifier to reduce waste (and thus make it more power efficient). This was first introduced by Qualcomm in 2013. Apple has been using envelope tracking since the iPhone 6.
Source (in German)