Early firmware had a known "ghost touch" issue, especially when charging. Later firmware updates (post-2017) recalibrated the Synaptics touch controller, eliminating false touches.
Return to fastboot getvar all and confirm version-main has changed to the new number.
The notification appeared on a Tuesday: “System Update Available – Firmware v3.2.1.”
Is your HTC One X9 feeling a bit sluggish? Whether you're looking to grab the latest official security patch or want to breathe new life into your device with a custom ROM, changing or updating your firmware can provide a much-needed performance boost.