According to respected analyst Ming-Chi Kuo, Apple's next-generation Mac mini would most likely have the same design as the present model.
Kuo noted in a quick tweet that the refreshed Mac mini will most likely keep the same form factor as the current model, which is an aluminium unibody design that Apple has utilised for every new Mac mini since 2010. Kuo previously stated that the new Mac mini will not be released until 2023.
Last year, leaker Jon Prosser said that Apple was working on a complete redesign for the mini desktop computer, switching to a smaller chassis with a "plexiglass-like" top. Kuo's allegation contradicts that claim.
For quite some time, Apple has been rumoured to be working on a new Mac mini. It updated the entry-level Mac mini with the M1 chip in November 2020, while the high-end model with an Intel processor is still the Space Gray model from 2018. The possibility of replacing this outdated high-end model with an Apple silicon machine was previously at the forefront of rumours around future Mac minis, but it now appears that both the entry-level and high-end models will be upgraded at the same time.
Apple "had plans" to introduce high-end versions of the Mac mini with M1 Pro and M1 Max CPUs, according to 9to5Mac, but these plans were "probably discarded" in favour of the Mac Studio. Apple is rumoured to be working on two new Mac mini models, one with the M2 processor and the other with the M2 Pro processor.