Original post with multiple alternatives to solve this: https://polkadot.polkassembly.io/post/84

Polkadot's current design allows validators to change the commission they receive for their work, affecting the rewards nominators might receive for backing them up. The changes are virtually instant and without prior notice to nominators. Although this can help nominators to be alert on the changes in their set, it is not ideal.

We want to introduce one particular solution and open a poll for it: invalidate nominations on commission increase.

This alternative assumes that changing the conditions (by increasing commission) of a tacit agreement should follow the cancellation of the agreement in question: increasing commissions is ultimately changing a contract with a nominator. If a validator wants to do this, the result would be the cancellation of the agreement between both.

• Although a very effective solution to protect nominators' rewards, this option can become an issue for validators' setup, given it is expected for validators to create and develop a community around them.
• The solution would work only when a validator increases the commission, not when a validator decreases it.
• If a validator goes offline, the commission is reset to zero and the validator has to set it again. The nominations are lost as well given the validator is offline, so going from 0 to whatever commission the validators chooses will not have a direct effect on nominations, since the validator already lost the nominations when the node went offline. For this reason offline status does not interfere with the mechanism.

The solution seems to offer the most customization while incentivizing honorable behavior - we have opened a poll here for your vote to understand the preference of the community. Please vote to the right and leave your comment, if any, below!

Please note that this is non binding and, if more than 50% of the participants on the poll are in favour of this solution, this will mean the Council will push for a serious discussion on implementation. If not, we will move to alternative solutions for discussion