Hello @ejain-bloom,

Is it possible that some Version names are similar across the mobile app vs. the web app? 

Using the most recently property and setting the platform equal to “web” in the right module will find the most recent active event that had platform equal to platform and the chart will output the version available at that time. Here is the documentation.

The version names are distinct (mobile app is at 3.x, web app is at 1.x).

Even with a filter on Platform = Web and having set “Most Recent Value”, both web and mobile app versions appear in the chart.

We do have users who use both the mobile and the web app, so maybe that’s confusing Amplitude?

Hey @ejain-bloom,
Can you check if your Platform property is getting updated along with the app version when a user toggles between the web and mobile apps? 

The Platform property on the user doesn’t seem to get updated, or perhaps there is a delay?

Here are the user properties on a web event:

Followed by a mobile event from the same user:

...but the user properties still show Platform=Web:

Hey @ejain-bloom 

In that case, you might want to read more here which explains how Amplitude updates user properties on its end. 

So it’s not possible to use Amplitude to get a correct answer to a question like “what percentage of users have upgraded to the latest version”, when users can be on more than one platform (each with its own versioning scheme)?

Depending on how your instrumentation is working and which of the three ways your properties are being applied, it’s worth to note the following to check in the edge cases - 

When a user property's value changes, Amplitude charts can show the user in both the new and the old user property categories. This overlap only applies for the specific day on which the property value changed.

Alternative way would be to send the data into two separate buckets if possible - one for web and one for mobile. We follow this approach and leverage the cross portfolio view and it has been helpful so far. 

@ejain-bloom I will reach out in a private thread as I need more personal information about your instrumentation in order to help.

By “separate buckets” do you mean separate projects? Looks like the “cross portfolio view” is a separate add-on, but good to know!

I suppose we could also capture the version number using two different, custom properties, rather than the built-in version property...

@ejain-bloom 
Yes, two separate projects.

We actually use the HTTP API for ingestion and thus pipe in the app version number as a custom user property.

So it turns out the version mixup may have been due to the fact that we don’t always set a version number in the web app. When no version number is set, Amplitude takes the previous seen version number for a user (which may be from the mobile app rather than the web app) and uses that 

Ah, there you go. Glad you were able to catch that.