Dear Amplitude Customers,
Once we discovered and verified this issue, we added a control in JS SDK 4.1.1 that has shown itself to be effective in mitigating this scenario, even as Amplitude cannot control it directly.
Many of our customers have updated the Amplitude JS SDK version in their applications. Unfortunately, some customers have yet to do so. As a result, we have concluded that it is appropriate at this time to deprecate all older versions of the JS SDK that lack this mitigation. As such, Amplitude will deprecate all versions of the JS SDK older than 4.1.1 on January 31, 2019, and beginning February 1, 2019, Amplitude will no longer support those versions of the JS SDK. This means that on February 1, 2019 we will stop collecting data from JS SDKs older than 4.1.1.
We will send additional reminders as the deadline approach. Please make sure to update your JS SDK version as soon as possible but no later than January 31, 2019 in order to avoid loss of service once support for the versions of the JS SDK older than 4.1.1 is turned off in the platform. You can find the latest version of our JS SDK here.
We appreciate your cooperation as we continue to improve data security. If you have any questions please reach out to your CSM or to firstname.lastname@example.org
Sr. Director of Customer Success