Error during "delta" application download

After enabling delta application updates on a RaspberryPi 3 running Resin 2.7.5 (prod), I get a bunch of these on the log, right after a new commit:

Failed to download application ‘’ due to ‘ESOCKETTIMEDOUT’

After several failures, the applications ends up downloading (after 4 or 5 tries) and deploys successfully.

Can you explain this behavior? Should I do something differently so delta updates work properly?

Thank you.

As of this morning, I see this also on Resin OS 2.7.5+rev1 (prod) and Supervisor 6.3.6 with Pi3 application.

Hello World!
I’ll put a test update onto a couple of my applications in a little while, and feed back with results here.
Sqweelygig (your friendly neighbourhood weekend support agent)

Well, that took longer than expected. My RPi3 application was on ResinOS 2.0.8!
I have confirmed that this does happen as reported, on both 2.7.5 and 2.7.8. Since the updates do eventually succeed, I’m not going to raise any alarm bells, but am going to make sure that the Monday shift sees this.

Ok. I guess I’ve also seen this on a Raspberry Pi Zero W running the latest version (2.2.0, if I’m not mistaken).
Just as you said, the update eventually succeeds, but I believe the data usage rises a bit, with each failed attempt.

I can confirm this error also occurs on a Raspberry Pi Zero W running 2.7.8.


I don’t think it’s new, it’s something new I’ve seen it plenty of times. Normally the update does complete eventually.

This error message is shown when the delta server (which calculates the diff between the source and target image) is taking some time to calculate the delta.
We’ve added some changes to the delta server so that the supervisor shows a friendlier message (i.e. “the server is still processing the delta”) instead of the scary error message, but it has yet to make it to production (and it’s indeed nothing to be alarmed).

The fix mentioned by Pablo above was deployed to production.