--- a/testing/mozharness/external_tools/robustcheckout.py
+++ b/testing/mozharness/external_tools/robustcheckout.py
@@ -44,18 +44,18 @@ try:
     from mercurial import configitems
     configitems.dynamicdefault
 except ImportError:
     configitems = None
 
 # Causes worker to purge caches on process exit and for task to retry.
 EXIT_PURGE_CACHE = 72
 
-testedwith = '3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7'
-minimumhgversion = '3.7'
+testedwith = '4.3 4.4 4.5 4.6 4.7 4.8'
+minimumhgversion = '4.3'
 
 cmdtable = {}
 
 # TRACKING hg43 Mercurial 4.3 introduced registrar.command as a replacement for
 # cmdutil.command.
 if util.safehasattr(registrar, 'command'):
     command = registrar.command(cmdtable)
 else:
@@ -83,23 +83,19 @@ def getvfs():
 
 def getsparse():
     from mercurial import sparse
     return sparse
 
 
 def supported_hg():
     '''Returns True if the Mercurial version is supported for robustcheckout'''
-    return util.versiontuple(n=2) in (
-        (4, 3),
-        (4, 4),
-        (4, 5),
-        (4, 6),
-        (4, 7),
-    )
+    return '.'.join(
+        str(v) for v in util.versiontuple(n=2)
+    ) in testedwith.split()
 
 
 if os.name == 'nt':
     import ctypes
 
     # Get a reference to the DeleteFileW function
     # DeleteFileW accepts filenames encoded as a null terminated sequence of
     # wide chars (UTF-16). Python's ctypes.c_wchar_p correctly encodes unicode
@@ -675,17 +671,22 @@ def _docheckout(ui, url, dest, upstream,
         # By default, Mercurial will ignore unknown sparse profiles. This could
         # lead to a full checkout. Be more strict.
         try:
             repo.filectx(sparse_profile, changeid=checkoutrevision).data()
         except error.ManifestLookupError:
             raise error.Abort('sparse profile %s does not exist at revision '
                               '%s' % (sparse_profile, checkoutrevision))
 
-        old_config = sparsemod.parseconfig(repo.ui, repo.vfs.tryread('sparse'))
+        # TRACKING hg48 - parseconfig takes `action` param
+        if util.versiontuple(n=2) >= (4, 8):
+            old_config = sparsemod.parseconfig(repo.ui, repo.vfs.tryread('sparse'), 'sparse')
+        else:
+            old_config = sparsemod.parseconfig(repo.ui, repo.vfs.tryread('sparse'))
+
         old_includes, old_excludes, old_profiles = old_config
 
         if old_profiles == {sparse_profile} and not old_includes and not \
                 old_excludes:
             ui.write('(sparse profile %s already set; no need to update '
                      'sparse config)\n' % sparse_profile)
         else:
             if old_includes or old_excludes or old_profiles: