Works with CiviCRM 4.2. It might not be supported anymore.
Send email notification to event speakers when a new individual registers.
Since CiviCRM 5.x, extension releases compatible with CiviCRM 5.0 are compatible with 5.0 and later. An extension release compatible with 5.25, for example, means that it requires CiviCRM 5.25 or later.