This is an unofficial list/changelog of new features and various changes to Stack Overflow and the Stack Exchange network.
It is maintained by the community, while a Stack Exchange employee changes the accepted answer to ensure that the latest changes remain on top (given default user settings).
To see the list in reverse chronological order (latest entry on top), sort answers by: Date created (newest first).
For those adding new features here: please post only feature changes that affect the whole network and have some global impact. i.e. bug fixes don't belong here, nor do mobile app updates.