We are not able to predict a date or an estimated date when s7 will be in redemption period, and it will depend on too many factors.
At present the maintenance/payout ratio is around 75%, when the ratio is up to 100% and last for 10 days, HashNest will announce s7's redemption period begin. Please pay attention to the risk of purchasing s7 at present, we don't accept any compensation or refund request after payment completed.
During redemption period, the market will be eventually closed for s7.
No plan of upgrading s7 to s9 at present.