Update: After extensive testing, we have certified MathType 7.4 for use with eXtyles.
eXtyles users who have MathType 6.9 installed can continue to use 6.9 or upgrade to 7.4.
For eXtyles users who have previously installed MathType 7.x, we recommend upgrading to 7.4 as soon as possible.
You can find more information about MathType here: https://docs.wiris.com/en/mathtype/start
For specifics on how to install MathType, see this FAQ.