upgrading.md

# Upgrading to 2.x

With the new major release version, the Spring Session team took the opportunity to make some non-passive changes.
The focus of these changes is to improve and harmonize Spring Session’s APIs as well as remove the deprecated components.

## Baseline Update

Spring Session 2.0 requires Java 8 and Spring Framework 5.0 as a baseline, since its entire codebase is now based on Java 8 source code.
See [Upgrading to Spring Framework 5.x](https://github.com/spring-projects/spring-framework/wiki/Upgrading-to-Spring-Framework-5.x) for more on upgrading Spring Framework.

## Replaced and Removed Modules

As a part of the project’s splitting of the modules, the existing `spring-session` has been replaced with the `spring-session-core` module.
The `spring-session-core` module holds only the common set of APIs and components, while other modules contain the implementation of the appropriate `SessionRepository` and functionality related to that data store.
This applies to several existing modules that were previously a simple dependency aggregator helper module.
With new module arrangement, the following modules actually carry the implementation:

* Spring Session for MongoDB

* Spring Session for Redis

* Spring Session JDBC

* Spring Session Hazelcast

Also, the following were removed from the main project repository:

* Spring Session Data GemFire

  * [`spring-session-data-geode`](https://github.com/spring-projects/spring-session-data-geode)

## Replaced and Removed Packages, Classes, and Methods

The following changes were made to packages, classes, and methods:

* `ExpiringSession` API has been merged into the `Session` API.

* The `Session` API has been enhanced to make full use of Java 8.

* The `Session` API has been extended with `changeSessionId` support.

* The `SessionRepository` API has been updated to better align with Spring Data method naming conventions.

* `AbstractSessionEvent` and its subclasses are no longer constructable without an underlying `Session` object.

* The Redis namespace used by `RedisOperationsSessionRepository` is now fully configurable, instead of being partially configurable.

* Redis configuration support has been updated to avoid registering a Spring Session-specific `RedisTemplate` bean.

* JDBC configuration support has been updated to avoid registering a Spring Session-specific `JdbcTemplate` bean.

* Previously deprecated classes and methods have been removed across the codebase

## Dropped Support

As a part of the changes to `HttpSessionStrategy` and its alignment to the counterpart from the reactive world, the support for managing multiple users' sessions in a single browser instance has been removed.
The introduction of a new API to replace this functionality is under consideration for future releases.