Can I use
?

XHTML served as application/xhtml+xml

- LS

A strict form of HTML, and allows embedding of other XML languages

IE

  1. 5.5 - 8: Not supported
  2. 9 - 10: Supported
  3. 11: Supported

Edge

  1. 12 - 84: Supported
  2. 85: Supported

Firefox

  1. 2 - 79: Supported
  2. 80: Supported
  3. 81 - 82: Supported

Chrome

  1. 4 - 84: Supported
  2. 85: Supported
  3. 86 - 88: Supported

Safari

  1. 3.1 - 13.1: Supported
  2. 14: Supported
  3. TP: Supported

Opera

  1. 9 - 69: Supported
  2. 70: Supported

iOS Safari

  1. 3.2 - 13.7: Supported
  2. 14.0: Supported

Opera Mini

  1. all: Supported

Android Browser

  1. 2.1 - 4.4.4: Supported
  2. 81: Supported

Blackberry Browser

  1. 7: Supported
  2. 10: Supported

Opera Mobile

  1. 10 - 12.1: Supported
  2. 46: Supported

Chrome for Android

  1. 85: Supported

Firefox for Android

  1. 79: Supported

IE Mobile

  1. 10: Supported
  2. 11: Supported

UC Browser for Android

  1. 12.12: Supported

Samsung Internet

  1. 4 - 11.2: Supported
  2. 12.0: Supported

QQ Browser

  1. 10.4: Supported

Baidu Browser

  1. 7.12: Not supported

KaiOS Browser

  1. 2.5: Supported

The XHTML syntax is very close to HTML, and thus is almost always (incorrectly) served as text/html on the web.

Resources:
Information on XHTML5
Wikipedia
WebPlatform Docs
Sub-features:
XHTML+SMIL animation