It's not officially supported. That and I just don't want to pay for another new phone. Official support right now is:

- Xperia X, Xperia XA2, Xperia XA2 Plus, Xperia XA2 Ultra.

I have seen that there is some community support for the Xperia X Compact though.

The newest Sony "compact", the XZ2 Compact, is almost as large as the original Xperia X now too.

  Galaxy S10+:        158 x 74 mm
  Xperia X:           143 x 69 mm
  Xperia XZ2 Compact: 135 x 65 mm
  Xperia X Compact:   129 x 65 mm
  iPhone SE:          124 x 59 mm
  Nokia N9:           117 x 61 mm

I think the perfect phone for me would be an N9/iPhone SE size phone with an iPhone X-style borderless screen and Meego or Sailfish OS.

Xperia X Compact is not officially supported, but a member of the community created a patcher that turns the official Xperua X Sailfish OS image into one you can use for X compact:

https://github.com/g7/sailfishx-patcher-f5321

After that all works, including OTA uogrades. A friend of mine flashed such a patched Sailfish OS image on his X compact and AFAIK all works fine for him. :)