I was referring only to static dependencies, like Guava for example. Static dependencies don't require ongoing "upkeep", so you really should allow your users to use an older version of your library/code, if that's what they really want to do.
When it comes to live services that you're actually running on a daily basis, like Google maps, forcing users to migrate makes a lot more sense.
Just because your older versions are available to users, doesn't mean you have to continuously maintain them. For example, I know plenty of teams still using Java 7, even though Oracle has EOLed it. The teams know the risk that they are taking, and have the flexibility to decide when they want to migrate to a newer version, and that's how it should be. I would never want to live in a world where Oracle can force me to migrate to Java 10 within a day of release.
When it comes to live services that you're actually running on a daily basis, like Google maps, forcing users to migrate makes a lot more sense.