till 21st july you can start the masternodes with 1000 ABS.
after then you need to upgrade you all masternodes to 2500 coins
the collateral for Masternodes is going to change in 8 days (21.07.18) to 2.5K
After the 25th the minimum protocol spork will be enabled, this will mean that old Masternodes will no longer be recognised on the Masternode list. At this point all old Masternodes will no longer receive rewards and must be upgrade to 2500 ABS to continue to work.
1000 ABS masternode will be disabled on 25 July.