After the publication of the Note,1 the author became aware of the paper by Anacleto and Ferreira.2 Results in the Note for two bodies with constant heat capacities were also obtained in that paper. This erratum does not affect any result or conclusion of the original Note.

1.
R. S.
Johal
, “
The law of entropy increase for bodies in mutual thermal contact
,”
Am. J. Phys.
91
,
79
–80 (
2023
).
2.
J.
Anacleto
and
J. M.
Ferreira
, “
Reversible versus irreversible thermalization of two finite blocks
,”
Eur. J. Phys.
37
,
022001
(
2016
).