No. See any of the papers, eg <a href="http:&#x2F;&#x2F;ssrg.nicta.com.au&#x2F;publications&#x2F;nictaabstracts&#x2F;Elphinstone_Heiser_13.abstract.pml" rel="nofollow">http:&#x2F;&#x2F;ssrg.nicta.com.au&#x2F;publications&#x2F;nictaabstracts&#x2F;Elphins...</a>. The maintenance effort is quite reasonable. They&#x27;ve managed to evolve, and continue to evolve, the kernel even with the ever more stricter properties proven about it.