was browsing the routerboot changelog, and stomped upon the latest entry back from last summer (June 2017)
What’s new in 3.40
removed support for QSFP28 swapped I2C;
there was a “poll” on the forum in last may about what kind of high speed interfaces the community wanna see on “big boxes”.
http://forum.mikrotik.com/t/which-types-of-ports-would-you-like-to-see-for-a-high-speed-router/108634/1
well, qsfp28 is for 100Gbps, as it can directly emit 4x25G (4xSFP28) with proper breakout cable.
nevertheless, there ain’t no Mikrotik device out there which could accommodate a qsfp28 pluggable. yet.
therefore this routerboot update from last year maybe hints a mystery-device to come…