No, there is no requirement to migrate any of your Flexacoin to Amp.

The only downside in not migrating your FXC to AMP is that if you do not migrate to Amp, your balance will no longer be used as collateral by Flexa Capacity after September 30, 2020–and will therefore not earn any network rewards after that point.

Please also note that Flexa has no plans to support Flexacoin in any Flexa products after September 30, 2020, because we believe that Amp improves upon Flexacoin in every way and opens up endless new possibilities for improving collateralization on the Flexa network that were never possible with Flexacoin.

That being said, if you would like to keep all or a portion of your Flexacoin balance as FXC, you are welcome to do so, and you will always be able to migrate your Flexacoin to Amp at any point in the future.