Text messages that we have all used over the years are archaic and awkward, but RCS promises to modernize messaging with features such as read receipts and file transfers. However, the implementation of RCS by carriers has been a real waste. Example: T-Mobile claims that the new Pixel 3a and 3a XL will not have RCS support on its network. We can safely assume that the existing 3 and 3 XL pixels (also available from T-Mobile) will be the same.

You can understand the lack of RCS with the previous Pixel phones on T-Mobile; he did not sell those directly. However, T-Mobile is now selling Pixel phones, but does not support RCS.

Google has RCS support in its Messages app. It works well for RCS on carriers like Verizon, but the T-Mobile RCS configuration is still cloudy. It has extended universal profile support to phones such as the Galaxy S7, S8, S9, Note 8, Note 9 and OnePlus 6T. We have contacted T-Mobile for clarification and we will update it if we get more details.