Motorola says that it will update the Verizon Moto Z2 Force to Android Pie to enable 5G Moto Mod support. However, "some US models" will not be updated to Pie. Because Motorola only mentions the Verizon model as the one getting Pie, that means that the AT&T, Sprint, and T-Mobile models will be stuck on Android Oreo.
In its forum post, Motorola explains that "delivering any Android upgrade is a complex process" and that it won't be updating these Moto Z2 Force models due to "a variety of reasons".
T-Mobile has confirmed that its Moto Z2 Force won't be updated to Pie, with a support team member saying that T-Mobile has "received word that this device will no longer be getting Android Pie."
The Moto Z2 Force launched with Android 7.1 Nougat and was updated to Android 8.0 Oreo, and the non-Verizon models will stay there. That's disappointing because at one time, Motorola was known for being one of the better Android device makers when it came to Android OS updates. Plus, Motorola's Moto Z line of phones was considered to be its flagship series, though that appears to be changing with the Moto Z4.