Introduction

Most java libraries and frameworks define a version baseline for either the Java JDK or other libraries it uses. The "baseline version" primarily means the minimum version required to run a Spring application. Correspondingly, Spring Framework 6 has baseline upgrades that are described in the following sections.

Java baseline upgrade

The java baseline for Spring 6 is Java 17, which is an LTS version that is released on September 14, 2021. I think it is a good choice to require Java 17 as a minimum because of the two years cadence that Java follows for LTS version releasing.

Java EE baseline upgrade

Spring 6 requires Jakarta EE 9 as a minimum, which will enforce you to use a web server that supports it and you will need also to do some renaming of packages (javax.* -> Jakarta.*) if you want to upgrade from Spring prior versions to Spring 6.