Wickham joined the club from Sunderland on 3rd August 2015, and had just a year left on his current contract with the Eagles.
The 26-year-old has 10 goals for the south London side in 42 appearances across all competitions, with the forward's most recent strike coming in the memorable FA Cup victory over Tottenham Hotspur back in January.
Upon signing the extension, Wickham said: “I’m pleased to have got everything sorted, so I can now fully focus on working my way back into the team during pre-season and the upcoming campaign. I hope I’ll be able to show that when fully fit I’m capable of playing a key part.
“It meant a lot that the club backed me after such a serious injury and I hope I’ll be able to repay that faith shown in me.”
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