Both my drivers had 1 race to go, just before our league race started i renewed their contract and both came up with retiring at the end of the season. I went on the marketplace to get 2 new drivers, and then say farewell to the current 2. There is no auction option, no sell option, only 'sack' and it want's me to pay out 53million to sack retiring drivers.. each.
Now having no auction or sell is silly because they have both have 49 races to go (which could have been 50) so still useable for a couple of season depending on the league, and they would be available for people to get the retiring driver achievement. The notion however of the contract payout for sacking them for 50+mil is ridiculous given that if i knew on contract renewal that they were going to retire i wouldn't have renewed them.
