I can update release content, that is to say:
- notes
- changelog
- release status

New SOAP method updateRelease()

Example:
/**
* updateRelease - update a release in the file release manager, in the package $package_id of the project $group_id with given values
*
* @param string $sessionKey the session hash associated with the session opened by the person who calls the service
* @param int $group_id the ID of the group we want to add the release
* @param int $package_id the ID of the package we want to add the release
* @param int $release_id the ID of the package we want to add the release
* @param string $notes the notes of the release we want to update
* @param string $changes the changes of the release we want to update
* @param int $status_id the ID of the status of the release we want to update
*
* @return boolean true if the release has been updated, false otherwise
*/
function updateRelease($sessionKey,$group_id,$package_id,$release_id,$notes,$changes,$status_id);