do not change after buy new plan 
Hello @Sirojiddin_Salohiddi ,
Sorry to hear you have encountered an issue with your upgraded plan, but we can certainly help you with this.
When upgrading from Community Edition to a Developer Edition plan, a new license key is provided. The new license needs to be activated on the device for the upgrade to complete.
May I ask you to please double check for a Diffblue email containing your new license & upgrade instructions? (please double check your email junk folder just in case)
If this has not come through I can contact you directly with your new license & upgrade instructions.
Kind Regards,
Shaun
Oh my bad, it worked now) sorry about this situation)
Hello @Sirojiddin_Salohiddi ,
Not a problem at all. Glad the issue is resolved and you have been able to update.
Don’t hesitate to reach out if you encounter any other challenges in the future.
Kind Regards,
Shaun