The Advanced Photon Source (APS) linac has reliably delivered high-quality electron beams for over 30 years. To support the APS Upgrade and ensure continued operation, a major refurbishment is underway. As part of this project, two of the linac's five operating radio frequency (RF) stations have been upgraded with solid-state modulator-powered klystrons and new digital low-level radio frequency (LLRF) systems. This upgrade has notably improved the linac's performance. This paper summarizes these improvements and outlines our next plans.