From Zerto Support:
Does vCenter 6.7 U3F is compatible with the version of Zerto?
As stated in Zerto interoperability matrix on page 7:
Zerto does support vCenter 6.7U3F
Zerto assumes that minor update releases are supported (for example, vCenter Server 5.5U1a, 5.5U1b or 5.5U1c), if the major update is supported.
vCenter version 6.7U3 is supported and thus the new build listed (6.7 Update 3f ) is also supported.