Aero Vodochody has found three parties willing to upgrade their L-39 jet trainers with new engines and systems.
By Airwolfhound from Hertfordshire, UK (L39C – RIAT 2014) [CC BY-SA 2.0], via Wikimedia Commons
The Breitling Jet Team, Draken International and Czech state firm LOM Praha will have new Williams International FJ44-4M engines installed on their jets. Not much is known regarding other upgrades.