At the risk of being argumentative I actually agree with the OP.. Requring a donation, isn't really a donation;
DONATION, contracts. The act by which the owner of a thing, voluntarily transfers the title and possession of the same, from himself to another person, without any consideration; a gift. (q.v.)
2. A donation is never perfected until it is has been accepted, for the acceptance (q.v.) is requisite to make the donation complete. Vide Assent, and Ayl. Pand. tit. 9 Clef des Lois Rom. h.t.
You are requiring payment in exchange for product (AB'z) and and services (Support), which makes it a payment, of a minimum amount, with the implied request that someone might be prepared to pay additionally for it if they feel it presents value for money.