In the context of products, the terms upgrade and downgrade (no hyphen, up and down no longer prefixes here, the two "words" are recognized and defined as such) have specific meanings.
Upgrading is the process of replacing a product with a newer version of the same product. In computing and consumer electronics an upgrade is generally a replacement of hardware, software or firmware with a newer or better version, in order to bring the system up to date or to improve its characteristics. (WP)
raise (something) to a higher standard, in particular improve (equipment or machinery) by adding or replacing components:
the cost of upgrading each workstation is around $300 (ODO)
reduce to a lower grade, rank, or level of importance:
some jobs had gradually been downgraded from skilled to semiskilled (ibid)
Note that downgrade is rarely used in the context of products.
The term "downgrade" became especially popularized during the days of Windows Vista, with users wanting to return to, or downgrade to (with some even calling it an "upgrade") Windows XP due to Vista's performance and familiarity issues. (WP:downgrade)
… hardware components may not be compatible after either an upgrade or downgrade, due to the non-availability of compatible drivers for the hardware … [emphasis mine] (WP)
The usual way to refer to upgrade/downgrade is to use the unambiguous phrase upgrade or downgrade as Wikipedia does above.
And, no, it's not rightgrade.