The more I read, write, and review technical reference docs, the more I find that super-short paragraphs, with lots of subheads, make info easier to find.
From the Gradle docs: https://docs.gradle.org/current/userguide/gradle_wrapper.html#sec:upgrading_wrapper
To Quote (use an image here):
Projects will typically want to keep up with the times and upgrade their Gradle version to benefit from new features and improvements. One way to upgrade the Gradle version is manually change the distributionUrl property in the Wrapper property file. The better and recommended option is to run the wrapper task and provide the target Gradle version as described in the section called “Adding the Gradle Wrapper”. Using the wrapper task ensures that any optimizations made to the Wrapper shell script or batch file with that specific Gradle version are applied to the project. As usual you’d commit the changes to the Wrapper files to version control.
Use the Gradle wrapper task to generate the wrapper, specifying a version. The default is the current version, which you can check by executing ./gradlew –version.