Hi [NAME],   For H740P, it follows the server's OS support. As previously checked, R440 supports 18.04 and 20.04 based on the OS compatibility matrix Shine shared. (Reference for H740P OS support: [URL] and [URL] So to answer your point 1, H740 should support 20.04.    For point 2, are you referring to warranty of the server? - If you have recently procured the server, I suggest you speak to your Dell account manager with regards of the downgrade changes to avoid any warranty voids.   
Hi team, We have procured R440 servers comes with H750 RAID card. And turns out that H750 has a minimum Ubuntu support at 20.04, while we're using 18.04 and has no upgrade plan in the following few quarters. Is it possible to replace H750 with H740, or any other way possible in order to have these servers join our Ubuntu18 server fleet? Thanks! Freddy
H750 downgrade to H740 for Ubuntu18.04