Branch and release

Branch and Release model

Branch	Version	Tags	Spring Boot Version
master	2.2.0.BUILD-SNAPSHOT		2.1.0.RELEASE
2.1.x	2.1.0.BUILD-SNAPSHOT	*2.1.0.M1	2.1.0.RELEASE
		...	...
2.0.x	2.0.8.BUILD-SNAPSHOT	*2.0.8.M1	2.0.3.RELEASE
		2.0.7	2.0.3.RELEASE
		2.0.6	2.0.3.RELEASE
		2.0.5	2.0.3.RELEASE
		2.0.4	2.0.3.RELEASE
		2.0.3	2.0.1.RELEASE
		2.0.2	2.0.1.RELEASE
		2.0.1	2.0.0.RELEASE
		2.0.0	2.0.0.RELEASE
		...	...
1.5.x	0.2.5.BUILD-SNAPSHOT		1.5.14.RELEASE
		0.2.4	1.5.11.RELEASE
		0.2.2	1.5.4.RELEASE
		0.2.1	1.5.4.RELEASE
		0.2.0	1.5.4.RELEASE
		...	...

* means we are working on this tag.

Steps of Spring version upgrade

Take spring version 2.2.0.RELEASE as example

• Upgrade spring version to 2.2.0.RELEASE, make changes for comparability.
• Branch out 2.2.x.
• Update master version to 2.3.0.BUILD-SNAPSHOT, as well as upgrade spring version to 2.3.0.BUILD-SNAPSHOT.
• Continue work on branch 2.2.x, then release 2.2.0.M1, 2.2.0.RC1 and so on.
• After branch 2.2.0.RC.X is stable enough and spring version 2.2.1.RELEASE available, we can release the final version 2.2.0.RELEASE.
• Finally, update branch 2.1.x version to 2.2.1.BUILD-SNAPSHOT and upgrade spring version to 2.2.1.RELEASE.