Microsoft is conducting a round of scheduled maintenance for Xbox 360 games and services, Major Nelson announced today on his blog. This will also affect the Xbox 360 games that play on Xbox One through backwards compatibility; there are more than 300 games in the catalog. The two-hour maintenance period starts at 4 AM ET on April 27 and runs until 6 AM ET. If you're playing an Xbox 360 game during this time--on Xbox 360 or Xbox One--you could get disconnected from Xbox Live "one or more times," Major Nelson said.
Major Nelson clarified that regular Xbox One games and services connected to the console are not going to be impacted by this round of maintenance. There is no word on what the round of Xbox 360 game maintenance is for. We'll report back with more details as they become available.