Apache Log4j 2 is not compatible with the previous versions. Please have the following in mind when upgrading to Log4j 2 in your project:
- Log4j 2.4 and greater requires Java 7, versions 2.0-alpha1 to 2.3 required Java 6.
- The XML configuration has been simplified and is not compatible with Log4j 1.x.
- Configuration via property files is supported from version 2.4, but is not compatible with Log4j 1.x.
- Configuration via JSON or YAML is supported, but these formats require additional runtime dependencies.
- Although Log4j 2 is not directly compatible with Log4j 1.x a compatibility bridge has been provided to reduce the need to make coding changes.