F-35 to receive software update this summer; full TR-3 upgrade timeline remains uncertain

Lockheed Martin plans to release a new software update for its F-35 fighter this summer, reports Defense One, marking a step toward the comprehensive Technology Refresh-3 (TR-3) upgrade. TR-3, encompassing both software and hardware enhancements, is essential for the subsequent Block 4 improvements, which aim to bolster the aircraft's combat capabilities. ​

Initially slated for completion in April 2023, the TR-3 upgrade has encountered multiple delays due to software development challenges. As of March 2025, Lockheed Martin has not established a firm delivery date for the full combat-ready version of the TR-3 package. Greg Ulmer, head of Lockheed's aeronautics division, emphasized that the final assessment and approval for full combat capability rest with the customer, acknowledging ongoing efforts to achieve this status. ​

Despite these delays, Lockheed Martin has made progress by delivering F-35s equipped with an initial version of the TR-3 configuration. In July 2024, the company began delivering aircraft with a "combat training-capable" version of TR-3, with plans to achieve full combat capability by early 2025. ​

The TR-3 upgrade is pivotal for the F-35 program, as it significantly enhances the jet's computational power, memory capacity, and sensor suite, improving situational awareness and data-sharing capabilities.