I've too heard the 6 year post OCU rumour. The additional rumour I've had though is that is would then start at circa £12K (top rate now) and go up annually about £1k to a top of about £19K. Those already in training to retain rights to the old scheme, applicable to new joiners only.
Nothing seen on paper at all to confirm it, just consistent, repeated rumours.
If it does happen it would truly be a 'retention' payment for those outside initial RoS.