http://411mania.com/movies/shrek-could-appear-in-puss-in-boots-2/
In an interview with Empire, Antonio Banderas hinted that Shrek could appear in Puss in Boots 2. Here are highlights:
On the rumors that Shrek could appear: “I heard some rumors that Shrek may be coming back. That would be great. Shrek doing a cameo… in MY movie? Uh, huh! Yeah, I’d like that.”
On the status of the sequel: “They are restructuring the script now. We started… but that’s the process. A lot of people participate in the creation of the script and the story and the narrative, everything. And they include you! They take you to California and you read the script with them, give them your ideas, and a couple of months later you see a new script where everything has been touched up.”
The last film was released 2011, and the last Shrek film debuted in 2010. Puss in Boots 2 had a release date of December 21, 2018 but was pulled from the schedule to account for Dreamworks’ plan to release two films a year. It’s current release date is unknown.