diff --git a/source/unified-test-format/unified-test-format.rst b/source/unified-test-format/unified-test-format.rst
index 97346604d8..6498e915ea 100644
--- a/source/unified-test-format/unified-test-format.rst
+++ b/source/unified-test-format/unified-test-format.rst
@@ -3,13 +3,13 @@ Unified Test Format
 ===================
 
 :Spec Title: Unified Test Format
-:Spec Version: 1.9
+:Spec Version: 1.9.1
 :Author: Jeremy Mikola
 :Advisors: Prashant Mital, Isabel Atkinson, Thomas Reggi
 :Status: Accepted
 :Type: Standards
 :Minimum Server Version: N/A
-:Last Modified: 2022-05-16
+:Last Modified: 2022-06-16
 
 .. contents::
 
@@ -420,7 +420,8 @@ The structure of this object is as follows:
   If this field is omitted, there is no authentication requirement.
 
 - ``csfle``: Optional boolean. If true, the tests MUST only run if the driver
-  supports Client-Side Field Level Encryption. If false, tests MUST only run if
+  and server support Client-Side Field Level Encryption. A server supports
+  CSFLE if it is version 4.2.0 or higher. If false, tests MUST only run if
   CSFLE is not enabled. If this field is omitted, there is no CSFLE requirement.
 
 Test runners MAY evaluate these conditions in any order. For example, it may be
@@ -3473,6 +3474,8 @@ spec changes developed in parallel or during the same release cycle.
 Change Log
 ==========
 
+:2022-06-16: Require server 4.2+ for ``csfle: true``.
+
 :2022-05-10: Add reference to Client Side Encryption spec under
              `ClientEncryption Operations`_.