Shimano Di2 firmware updates have gotten more meaningful with version 4.5.0. As someone who’s dealt with cold weather shifting issues firsthand, I was genuinely relieved to see this release. Today, I will share what actually changed.
That’s what makes firmware updates endearing to us Di2 users — when they fix real problems we’ve been complaining about.
The Cold Weather Fix
Probably should have led with this section, honestly — cold weather shift delays were the most frustrating Di2 issue.
Version 4.5.0 addresses delayed shift response in cold temperatures. The system now responds normally even when frozen fingers are pressing frozen shifters on frozen morning rides.
Wireless Improvements
But what else changed? In essence, better signal stability between hood shifters and rear derailleur.
The wireless connection occasionally dropped on older firmware, especially with third-party bike computers nearby. This update improves pairing reliability with Garmin, Wahoo, and Hammerhead units.
How to Update
I’m apparently in the camp that updates firmware immediately when it fixes known issues. Frustrated by waiting and hoping problems resolve themselves, I updated the day this released.
Connect your Di2 system to the E-Tube Project app on your phone. Ensure battery is above 50%. The update takes about 3 minutes. Perform micro-adjust after updating if shifting feels slightly off — this is normal.
Other Improvements
Synchro-shift responds faster. Multi-shift handling — pushing the lever multiple times quickly — works more reliably. Small improvements that add up during actual riding.
Making the Call
If you ride Di2, update to 4.5.0. The cold weather fix alone justifies the three minutes. Wireless stability improvements reduce frustration with bike computers. Small polish that makes an already excellent system better.
