diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 403e463845d9455cbe4cd3f27caac7b5e73dd16f..2d8c24c0dbcd79053a5c11409daf079905724139 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,5 +1,5 @@
 ###############################################################################
-# (c) Copyright 2018 CERN for the benefit of the LHCb Collaboration           #
+# (c) Copyright 2018-2021 CERN for the benefit of the LHCb Collaboration      #
 #                                                                             #
 # This software is distributed under the terms of the GNU General Public      #
 # Licence version 3 (GPL Version 3), copied verbatim in the file "COPYING".   #
@@ -16,3 +16,29 @@ check-copyright:
   script:
     - curl -o lb-check-copyright "https://gitlab.cern.ch/lhcb-core/LbDevTools/raw/master/LbDevTools/SourceTools.py?inline=false"
     - python lb-check-copyright origin/${TARGET_BRANCH}
+
+check-formatting:
+  image: gitlab-registry.cern.ch/lhcb-docker/style-checker
+  script:
+    - if [ ! -e .clang-format ] ; then
+    -   curl -o .clang-format "https://gitlab.cern.ch/lhcb-core/LbDevTools/raw/master/LbDevTools/data/default.clang-format?inline=false"
+    -   echo '.clang-format' >> .gitignore
+    -   git add .gitignore
+    - fi
+    - curl -o lb-format "https://gitlab.cern.ch/lhcb-core/LbDevTools/raw/master/LbDevTools/SourceTools.py?inline=false"
+    - python lb-format --format-patch apply-formatting.patch origin/${TARGET_BRANCH}
+  artifacts:
+    paths:
+      - apply-formatting.patch
+    when: on_failure
+    expire_in: 1 week
+
+python-linting:
+  tags:
+    - cvmfs
+  script:
+    - . /cvmfs/lhcb.cern.ch/lib/LbEnv.sh
+    # Only run the pyflakes linter and a few select pycodestyle errors
+    # Lint a single file because much of the code in DaVinci is yet to be checked whether it will be kept for run 3.
+    # This one file has been updated to pass the linter checks!
+    - flake8 --exclude '*.opts.py' --select=F,E71,E9,W1,W6 $(find Phys/DaVinci -name 'ConfigurationUpgrade.py')
diff --git a/Phys/DaVinci/python/DaVinci/configurations.py b/Phys/DaVinci/python/DaVinci/configurations.py
index fe2b97813f7dbb52f53c031f7396a7f85c0ae197..7048daa80e7eba0f4f7ff293563702bf39af81e3 100644
--- a/Phys/DaVinci/python/DaVinci/configurations.py
+++ b/Phys/DaVinci/python/DaVinci/configurations.py
@@ -1,5 +1,5 @@
 ###############################################################################
-# (c) Copyright 2020 CERN for the benefit of the LHCb Collaboration           #
+# (c) Copyright 2020-2021 CERN for the benefit of the LHCb Collaboration      #
 #                                                                             #
 # This software is distributed under the terms of the GNU General Public      #
 # Licence version 3 (GPL Version 3), copied verbatim in the file "COPYING".   #
@@ -8,13 +8,12 @@
 # granted to it by virtue of its status as an Intergovernmental Organization  #
 # or submit itself to any jurisdiction.                                       #
 ###############################################################################
+"""
+Define configurations for applications, algorithms and external services.
+"""
 
-from GaudiConfig2 import Configurables as C
-from DaVinci.configOptions import get_slot_value
+from DaVinci.configOptions import get_slot_value, get_default_value
 
-################################################################################
-# Define configurations for applications and algorithms
-#
 
 def configure_app_mgr(appMgr, slots, config):
     """
@@ -25,16 +24,18 @@ def configure_app_mgr(appMgr, slots, config):
         if c.name == 'MessageSvc':
             messageSvc = c
 
-    appMgr.EvtMax = get_slot_value(slots,"EvtMax")
+    appMgr.EvtMax = get_slot_value(slots, "EvtMax")
     appMgr.HistogramPersistency = 'ROOT'
     appMgr.AuditAlgorithms = True
 
-    appMgr.ExtSvc = [c for c in config
-                     if c.__component_type__ == 'Service'
-                     and c.name not in ['ApplicationMgr']]
-    appMgr.TopAlg = [c for c in config
-                     if c.__component_type__ == 'Algorithm'
-                     and c.name not in ['ApplicationMgr']]
+    appMgr.ExtSvc = [
+        c for c in config if c.__component_type__ == 'Service'
+        and c.name not in ['ApplicationMgr']
+    ]
+    appMgr.TopAlg = [
+        c for c in config if c.__component_type__ == 'Algorithm'
+        and c.name not in ['ApplicationMgr']
+    ]
 
 
 def configure_init(dvInit, slots):
@@ -44,10 +45,6 @@ def configure_init(dvInit, slots):
     dvInit.Increment = get_slot_value(slots, "PrintFreq")
 
 
-################################################################################
-# Define configurations for external services
-#
-
 def configure_timing(auditor, timer, sequencer):
     """
     Configuration of timing auditors.
@@ -60,15 +57,15 @@ def configure_options_root_ntuples(svc, slots):
     """
     Configuration of output .root ntuples
     """
-    for _line in svc.Output :
-        if 0 <= _line.find ('FILE1') :
+    for _line in svc.Output:
+        if 0 <= _line.find('FILE1'):
             log = get_slot_value(slots, "Log")
-            log.warning ('Replace NTuple-LUN FILE1: ' + _line )
-            svc.Output.remove ( _line )
+            log.warning('Replace NTuple-LUN FILE1: ' + _line)
+            svc.Output.remove(_line)
     tupleFile = get_slot_value(slots, "TupleFile")
     tupleStr = "FILE1 DATAFILE='%s' TYP='ROOT' OPT='NEW'" % tupleFile
-    svc.Output += [ tupleStr ]
-    svc.OutputLevel  = 1
+    svc.Output += [tupleStr]
+    svc.OutputLevel = 1
 
 
 def configure_event_persistency(svc):
@@ -95,5 +92,5 @@ def configure_event_selector(svc, slots):
     if printFreq == 0:
         printFreq = get_default_value("PrintFreq")
         log = get_slot_value(slots, "Log")
-        log.warning("Print frequency cannot be 0. Set to %f." %printFreq)
+        log.warning("Print frequency cannot be 0. Set to %f." % printFreq)
     svc.PrintFreq = printFreq