Loss of event registration

[jemutorres]

We have a PWA developed with Flutter in which we are using this SDK to log user events.The installation of the SDK was done following the installation guide: https://pub.dev/packages/mixpanel_flutter

For months we have been analyzing weekly event logs in which we can see a pattern that is reproduced during the weeks.

A few weeks ago we noticed a drastic drop in the number of logged events so we started to investigate a possible problem with your SDK. The version of the Flutter SDK we were using is 2.1.1 and 2.47.0 for the JS version.

Upon investigation we saw that the number of events had decreased after the (automatic) upgrade of your JS version from 2.47.0 to 2.48.0. Finally, and after a lot of research work, we had to upgrade the Flutter version from 2.1.1 to 2.2.0. After this change we returned to have adequate records to the pattern that had been defined, even with the increase of events that our business requires in the dates in which we find ourselves.

In the following screenshot you can see the general pattern (Oct 1 - Nov 6). The errors in event registrations are clearly seen from November 6 onwards, where they have decreased considerably. With the update, 4 Dec, we see how the numbers improve to the point of increasing significantly due to our business model.

We have compared all this data with other platforms we use (Analytics). Both show similar data, except for Mixpanel.

After all this, we understand that there are incompatibilities between Flutter SDK version 2.1.1 and JS version 2.48.X.

We have reviewed the file "assets/packages/mixpanel_flutter/assets/mixpanel.js" and we see that it includes the loading of a script at https://cdn.mxpnl.com/libs/mixpanel-2-latest.min.js. This script is NOT versioned.

This is what led to the error as the version we had (2.1.1) and the version of JS that was running (2.48.1) are not aligned.

We request the following:

1. Publish in your CDN the different versions of the JS libraries in order not to force us to use the latest "2-latest.min.js"
2. Modify the Flutter SDK snippet to point to a specific version of the JS library.

With these we will be able to maintain compatibility between Flutter / JS libraries and, if necessary, notify through the documentation the mandatory update of the Flutter or JS library.

On the other hand, would it be possible to identify in your system the events that we have lost?

Thanks!

[jemutorres]

Please @zihejia @jaredmixpanel, it is very important that this issue is reviewed. After the update the data is being recorded correctly.

I am afraid that we will again have a significant loss of data if discrepancies between the Flutter and JS versions occur again.

Thanks!