• Minimum Gradle version has been bumped to 7.1
• Minimum JDK version has been bumped to 11 (even though this is not guaranteed by tests, Gradle can run with a Java 8 JVM, but must use a JDK 11 toolchain –or newer– for Java compilation)
• isEnabled and isCompilingTestOnlyCode properties have been renamed to enabled and compilingTestOnlyCode in Kotlin DSL, to align with the core Gradle practice of not having such is prefixes in Kotlin DSL, or different property names between Groovy DSL and Kotlin DSL
• other small changes (mostly internal, including a rewrite from Kotlin to Java), but that do not break binary compatibility for common usage, so plugins compiled against previous versions should continue to work

A note regarding the rewrite to Java, before I get questions about it: as much as I like Kotlin, I'm more familiar with Java tooling (specifically Error Prone and NullAway) and Java compatibility rules, and Android Lint is too heavyweight to my tastes.