The Rebbe blesses the recipient with a kosher and joyful Pesach and true freedom from all worries. He emphasizes joyful service of Hashem year-round and includes shmurah matzah as a remembrance of the Korban Pesach, with a hope for the Beis HaMikdash to be rebuilt soon.
https://www.torahrecordings.com/rebbe/igroskodesh/015/008/5375