Markdown

[Kilkenni]

I'm very new to RSStT. Native Telegram posts can use Markdown, so I wonder if crossposts from RSS made with RSStT will format the result accordingly if appropriate Markdown elements (like making text bold) are present in the source.

[Rongronggg9]

A valid RSS can only contain HTML according to the specification. If an RSS does contain Markdown, it is expected to be rendered as is on almost all RSS aggregators.
Telegram itself, does not "natively" support Markdown. It is just official clients that convert them into some internal formatting representations. RSStT converts HTML to such internal formatting representations, but never does the same thing for Markdown because of the mentioned reason.