According to Linus Torvalds, work on Linux kernel 4.9 is almost finished, and while things have not been so bad during its entire development cycle, the need for an eighth Release Candidate was imperative to ensure everything is well-tested and polished before the Linux 4.9 kernel series gets promoted to the stable channel.
“So if anybody has been following the git tree, it should come as no surprise that I ended up doing an rc8 after all: things haven’t been bad, but it also hasn’t been the complete quiet that would have made me go ‘no point in doing another week’,” said Linus Torvalds in the mailing list announcement.
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