This dynamic content is normally a part of a multipart MIME message.
Should be opened with an external viewer in case the e-mail client program can not display it inline.
Regarding the MS teams, plain text messaging covers a huge part of use cases, provided the third party client implementation warns the user about limited rendering support, allowing fallback to genuine MS client.
Regarding the MS teams, plain text messaging covers a huge part of use cases, provided the third party client implementation warns the user about limited rendering support, allowing fallback to genuine MS client.