To address the notion of “little or no change/improvement,” you could consider trying to somehow find a way to use the fairly idiomatic “maintaining/replacing the status quo,” perhaps sarcastically, if that's appropriate, together with an appropriate quip, for example:
Congratulations, you’ve succeeded in replacing the status quo with
[essentially] the same old thing;
Congratulations, you’ve succeeded
in replacing the statu quo with the status quo;
I’m sure the two percent are pleased with your efforts to maintain the status quo; or
With change like that who needs the status quo.
status quo noun (usually the status quo)
The existing state of affairs, especially regarding social or political issues:
“they have a vested interest in maintaining the status quo”
(definition from Oxford Dictionaries, but not the 4 sarcastic "usage examples")
For an option that doesn’t explicitly mention “the status quo” and whose sarcasm is a bit more subtle, you could perhaps comment on such an upgrade as follows:
Your recent upgrade gives literal meaning to the old adage about how
the more things change, the more they stay the same.
(cf: the original French version and its accepted figurative/philosophical meaning below from ‘Dictionary of Unfamiliar Words by Diagram Group’ via ‘The Free Dictionary by Farlex’)
plus ça change
A French phrase, shortened from plus ça change, plus c’est la même chose, meaning the more it changes the more it remains the same, used to imply that apparent change to something is merely superficial and does not affect its essence.
Your recently added list of options under consideration, especially the “… forgotten to merely unsupported” one prompts me to offer “[Your old car is] gone but not forgotten” (not in the standard, "we'll always remember our fallen heroes" sense, but in the strained sense that the old item and its problems are gone but the barely improved, similarly old replacement will be a constant reminder of them), which in turn leads to the less idiomatic variation “[Your old car is] gone, but just barely” (again, not in the more obvious “just recently” sense, but rather in the admittedly strained sense of “not really”).
(similar non-standard, albeit not totally related example usage of “Gone but not forgotten” from ‘beaut[dot]ie’ and slightly out of context use of “gone but not really” from ‘Writing Back: American Expatriates' Narratives of Return’ by Susan Winnett, via ‘Google Books’)