For the sake of completeness, let me add the references of the published version in Publ. RIMS that appeared earlier in March this year (should be rather a comment, but the references are too long for that):
Mochizuki, Shinichi, Inter-universal Teichmüller theory. I: Construction of Hodge theaters, Publ. Res. Inst. Math. Sci. 57, No. 1-2, 3-207 (2021). ZBL1465.14002.
Mochizuki, Shinichi, Inter-universal Teichmüller theory. II: Hodge-Arakelov-theoretic evaluation, Publ. Res. Inst. Math. Sci. 57, No. 1-2, 209-401 (2021). ZBL1465.14003.
Mochizuki, Shinichi, Inter-universal Teichmüller theory. III: Canonical splittings of the log-theta-lattice, Publ. Res. Inst. Math. Sci. 57, No. 1-2, 403-626 (2021). ZBL1465.14004.
Mochizuki, Shinichi, Inter-universal Teichmüller theory. IV: Log-volume computations and set-theoretic foundations, Publ. Res. Inst. Math. Sci. 57, No. 1-2, 627-723 (2021). ZBL1465.14005.
(Peter Scholze indicates in his reviewreview that the versions do not differ with respect to the issues Stix and he raised in 2018).