If you want to keep an eye on upcoming features on Mastodon, there's an official roadmap page at:
➡️ https://joinmastodon.org/roadmap
The abbreviations before each item indicate which platform the feature is for:
MAS = Core Mastodon functionality and the official web interface, these may appear in third party apps if their developers choose to add them
IOS = The official iPhone/iPad app
AND = The official Android app
(Don't know what numbers or bar charts next to the abbreviations mean though!)