From an IT PM perspective:

To add, when releasing a new product - always have 1 month running period for both applications (old/new). This is for failback purposes, in case the new one is full of issues, they can always revert back to the old application while fixing the new one https://twitter.com/hyunsiklovesyou/status/1264770170775465987">https://twitter.com/hyunsiklo...

Timeline wise, they could have released the beta version of the app 1 to 2 months prior to contract end with daum (possibly the reason for sudden move) https://abs.twimg.com/emoji/v2/... draggable="false" alt="🤔" title="Thinking face" aria-label="Emoji: Thinking face"> This will give people enough time to adjust to the new application.

Stakeholder management is key.

Also, they should have done performance testing prior to releasing, though it& #39;s not the most accurate way - because you really can& #39;t replicate the production environment - but they will be able to capture some, if not most, of the possible behavioral issues from the app