diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 83aaa81..d63f8a4 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -1,16 +1,16 @@
 version: 2
 
 build:
-    os: ubuntu-22.04
-    tools:
-        python: "3.10"
+  os: ubuntu-22.04
+  tools:
+    python: "3.12"
 
 python:
-    install:
-        - method: pip
-          path: .
-          extra_requirements:
-            - docs
+  install:
+    - method: pip
+      path: .
+      extra_requirements:
+        - docs
 
 sphinx:
-    configuration: docs/conf.py
+  configuration: docs/conf.py
diff --git a/tests/testdata/case.yml b/tests/testdata/case.yml
index d2e1317..872ea20 100644
--- a/tests/testdata/case.yml
+++ b/tests/testdata/case.yml
@@ -54,11 +54,11 @@ masterdata:
       uuid: 12345678-1234-1234-1234-123456789012
 
 tracklog:
-  - datetime: '2020-10-28T14:28:02'
+  - datetime: '2020-10-28T14:28:02Z'
     user:
       id: testuser
     event: created
-  - datetime: '2020-10-28T14:46:14'
+  - datetime: '2020-10-28T14:46:14Z'
     user: 
       id: testuser
     event: updated
diff --git a/tests/testdata/surface.yml b/tests/testdata/surface.yml
index 48297c9..050d844 100644
--- a/tests/testdata/surface.yml
+++ b/tests/testdata/surface.yml
@@ -3,11 +3,11 @@ version: "0.12.0" # including for REP and others to build logic on.
 source: fmu # always included, and always this value if FMU made it. For quick identification for external consumers.
 
 tracklog:
-  - datetime: '2020-10-28T14:28:02'
+  - datetime: '2020-10-28T14:28:02Z'
     user:
       id: testuser
     event: created
-  - datetime: '2020-10-28T14:46:14'
+  - datetime: '2020-10-28T14:46:14Z'
     user: 
       id: testuser
     event: updated