--- a/hgext/hgmo/__init__.py
+++ b/hgext/hgmo/__init__.py
@@ -100,16 +100,19 @@ from mercurial.hgweb.protocol import (
 OUR_DIR = os.path.dirname(__file__)
 ROOT = os.path.normpath(os.path.join(OUR_DIR, '..', '..'))
 execfile(os.path.join(OUR_DIR, '..', 'bootstrap.py'))
 
 import mozautomation.commitparser as commitparser
 import mozhg.mozbuildinfo as mozbuildinfo
 
 
+minimumhgversion = '3.8'
+testedwith = '3.8'
+
 cmdtable = {}
 command = cmdutil.command(cmdtable)
 
 
 def addmetadata(repo, ctx, d, onlycheap=False):
     """Add changeset metadata for hgweb templates."""
     description = encoding.fromlocal(ctx.description())
 
@@ -390,16 +393,17 @@ def automationrelevancewebcommand(web, r
     repo = web.repo
     deletefields = set([
         'bookmarks',
         'branch',
         'branches',
         'changelogtag',
         'child',
         'inbranch',
+        'parent',
         'phase',
         'tags',
     ])
 
     csets = []
     # Query an unfiltered repo because sometimes automation wants to run against
     # changesets that have since become hidden. The response exposes whether the
     # requested node is visible, so consumers can make intelligent decisions
@@ -408,19 +412,19 @@ def automationrelevancewebcommand(web, r
         entry = webutil.changelistentry(web, ctx, tmpl)
         # Some items in changelistentry are generators, which json.dumps()
         # can't handle. So we expand them.
         for k, v in entry.items():
             # "files" is a generator that attempts to call a template.
             # Don't even bother and just repopulate it.
             if k == 'files':
                 entry['files'] = sorted(ctx.files())
-            # "parent" is a generator in 3.6 and a lambda in 3.7+.
-            elif k == 'parent' and not isinstance(v, types.GeneratorType):
-                entry['parent'] = list(v())
+            elif k == 'allparents':
+                entry['parents'] = [p['node'] for p in v()]
+                del entry['allparents']
             # These aren't interesting to us, so prune them. The
             # original impetus for this was because "changelogtag"
             # isn't part of the json template and adding it is non-trivial.
             elif k in deletefields:
                 del entry[k]
             elif isinstance(v, types.GeneratorType):
                 entry[k] = list(v)
 

--- a/hgext/hgmo/tests/test-automationrelevant-obsolete.t
+++ b/hgext/hgmo/tests/test-automationrelevant-obsolete.t
@@ -97,17 +97,19 @@ Unless --hidden is used
         "desc": "file1 1",
         "extra": {
           "branch": "default"
         },
         "files": [
           "file1"
         ],
         "node": "11743f8081842eb047711e85120177ed46be343e",
-        "parent": [],
+        "parents": [
+          "d406a5ad38f255efb8657338e56a2bd6b8149cca"
+        ],
         "pushdate": [
           \d+, (re)
           0
         ],
         "pushhead": "3208166ea10954e86c390c32fe6f7166f06161b2",
         "pushid": 3,
         "pushnodes": [
           "11743f8081842eb047711e85120177ed46be343e",
@@ -128,17 +130,19 @@ Unless --hidden is used
         "desc": "file1 2",
         "extra": {
           "branch": "default"
         },
         "files": [
           "file1"
         ],
         "node": "3208166ea10954e86c390c32fe6f7166f06161b2",
-        "parent": [],
+        "parents": [
+          "11743f8081842eb047711e85120177ed46be343e"
+        ],
         "pushdate": [
           \d+, (re)
           0
         ],
         "pushhead": "3208166ea10954e86c390c32fe6f7166f06161b2",
         "pushid": 3,
         "pushnodes": [
           "11743f8081842eb047711e85120177ed46be343e",

--- a/hgext/hgmo/tests/test-automationrelevant.t
+++ b/hgext/hgmo/tests/test-automationrelevant.t
@@ -129,17 +129,19 @@ web command for exposing automation rele
         "desc": "push 1 commit 1",
         "extra": {
           "branch": "default"
         },
         "files": [
           "foo"
         ],
         "node": "0a971221ac36075c184743cba0490681eadca983",
-        "parent": [],
+        "parents": [
+          "55482a6fb4b1881fa8f746fd52cf6f096bb21c89"
+        ],
         "pushdate": [
           \d+, (re)
           0
         ],
         "pushhead": "cb5c79007e91b09a4ba7ebe9210311491d09e96e",
         "pushid": 2,
         "pushnodes": [
           "0a971221ac36075c184743cba0490681eadca983",
@@ -160,17 +162,19 @@ web command for exposing automation rele
         "desc": "push 1 commit 2",
         "extra": {
           "branch": "default"
         },
         "files": [
           "foo"
         ],
         "node": "cb5c79007e91b09a4ba7ebe9210311491d09e96e",
-        "parent": [],
+        "parents": [
+          "0a971221ac36075c184743cba0490681eadca983"
+        ],
         "pushdate": [
           \d+, (re)
           0
         ],
         "pushhead": "cb5c79007e91b09a4ba7ebe9210311491d09e96e",
         "pushid": 2,
         "pushnodes": [
           "0a971221ac36075c184743cba0490681eadca983",
@@ -191,17 +195,19 @@ web command for exposing automation rele
         "desc": "push 2 commit 1",
         "extra": {
           "branch": "default"
         },
         "files": [
           "foo"
         ],
         "node": "13855aae8fb3291c663ff46a8510c0e3fa673a4c",
-        "parent": [],
+        "parents": [
+          "cb5c79007e91b09a4ba7ebe9210311491d09e96e"
+        ],
         "pushdate": [
           \d+, (re)
           0
         ],
         "pushhead": "5d04c4fd236c19e241d1587e120b39840344eee8",
         "pushid": 3,
         "pushnodes": [
           "13855aae8fb3291c663ff46a8510c0e3fa673a4c",
@@ -223,17 +229,19 @@ web command for exposing automation rele
         "desc": "push 2 commit 2",
         "extra": {
           "branch": "default"
         },
         "files": [
           "foo"
         ],
         "node": "66a66c6c6ae312ec88240754300468a6cea8f71d",
-        "parent": [],
+        "parents": [
+          "13855aae8fb3291c663ff46a8510c0e3fa673a4c"
+        ],
         "pushdate": [
           \d+, (re)
           0
         ],
         "pushhead": "5d04c4fd236c19e241d1587e120b39840344eee8",
         "pushid": 3,
         "pushnodes": [
           "13855aae8fb3291c663ff46a8510c0e3fa673a4c",
@@ -255,17 +263,19 @@ web command for exposing automation rele
         "desc": "push 2 commit 3",
         "extra": {
           "branch": "default"
         },
         "files": [
           "foo"
         ],
         "node": "5d04c4fd236c19e241d1587e120b39840344eee8",
-        "parent": [],
+        "parents": [
+          "66a66c6c6ae312ec88240754300468a6cea8f71d"
+        ],
         "pushdate": [
           \d+, (re)
           0
         ],
         "pushhead": "5d04c4fd236c19e241d1587e120b39840344eee8",
         "pushid": 3,
         "pushnodes": [
           "13855aae8fb3291c663ff46a8510c0e3fa673a4c",