How to upgrade Droid:

1. Under the lib folder, replace droid-container-6.5.jar, droid-core-6.5.jar and droid-core-interfaces-6.5.jar with newer version.
2. Edit FFDroidIdentificationPlugin.java- Change the AGENT_VERSION variable to the new version.
3. Edit FFDroidIdentificationPlugin.java- Change the SIG_VERSION variable to the new version.
4. Increase the pl:version in the src/PLUGIN-INF/metadata_FFDroidIdentificator.xml
5. Under the conf folder, replace DROID_SignatureFile.xml with the related one from: https://www.nationalarchives.gov.uk/aboutapps/pronom/droid-signature-files.htm
6. Under the conf folder, replace container-signature.xml with the related one from: https://www.nationalarchives.gov.uk/aboutapps/pronom/droid-signature-files.htm
7. Build the plugin with command line: $ant