diff --git a/DQMServices/Components/python/HTTP.py b/DQMServices/Components/python/HTTP.py
index 3c6c2dd26d36e..e5e54c6402d2b 100644
--- a/DQMServices/Components/python/HTTP.py
+++ b/DQMServices/Components/python/HTTP.py
@@ -1,5 +1,5 @@
 from builtins import range
-from cStringIO import StringIO
+from io import StringIO
 from pycurl import *
 
 class RequestManager:
diff --git a/DQMServices/Components/python/X509.py b/DQMServices/Components/python/X509.py
index b5fe9f8ad5c0f..c85ff3280e9c7 100644
--- a/DQMServices/Components/python/X509.py
+++ b/DQMServices/Components/python/X509.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 import os, os.path
 from getpass import getpass
 
diff --git a/DQMServices/Components/scripts/dqm-access b/DQMServices/Components/scripts/dqm-access
index 179622b638f79..38a1c8970958c 100755
--- a/DQMServices/Components/scripts/dqm-access
+++ b/DQMServices/Components/scripts/dqm-access
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 from DQMServices.Components.HTTP import RequestManager
 from DQMServices.Components.X509 import SSLOptions
diff --git a/DQMServices/Components/scripts/dqm-grep b/DQMServices/Components/scripts/dqm-grep
index bbb8374a1baa3..5ef00a7cc53af 100755
--- a/DQMServices/Components/scripts/dqm-grep
+++ b/DQMServices/Components/scripts/dqm-grep
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Usage: dqm-grep -f PATTERN -e EXPRESSION [OPTIONS]
 
diff --git a/DQMServices/Components/scripts/dqm-ls b/DQMServices/Components/scripts/dqm-ls
index 19975dfea6294..a80b32fc9ba6f 100755
--- a/DQMServices/Components/scripts/dqm-ls
+++ b/DQMServices/Components/scripts/dqm-ls
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Usage: dqm-ls [-s SERVER] [-n CONNECTIONS]
 
diff --git a/DQMServices/Components/scripts/dqm-mbProfile.py b/DQMServices/Components/scripts/dqm-mbProfile.py
index 9b50bd7601065..80570c37bdc52 100755
--- a/DQMServices/Components/scripts/dqm-mbProfile.py
+++ b/DQMServices/Components/scripts/dqm-mbProfile.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 import os
 import collections
diff --git a/DQMServices/Components/scripts/dqmiodatasetharvest.py b/DQMServices/Components/scripts/dqmiodatasetharvest.py
index efd02ba32af45..9bffce24d1e76 100755
--- a/DQMServices/Components/scripts/dqmiodatasetharvest.py
+++ b/DQMServices/Components/scripts/dqmiodatasetharvest.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 from __future__ import print_function
 import re
 import json
diff --git a/DQMServices/Components/scripts/dqmiolumiharvest.py b/DQMServices/Components/scripts/dqmiolumiharvest.py
index c9b771e4741aa..3b331d2ad8f0a 100755
--- a/DQMServices/Components/scripts/dqmiolumiharvest.py
+++ b/DQMServices/Components/scripts/dqmiolumiharvest.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 from __future__ import print_function
 import os
 import json
diff --git a/DQMServices/Components/scripts/root2sqlite.py b/DQMServices/Components/scripts/root2sqlite.py
index 66a0a8d711a3b..3da3bdf0a0715 100755
--- a/DQMServices/Components/scripts/root2sqlite.py
+++ b/DQMServices/Components/scripts/root2sqlite.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 from __future__ import print_function
 import re
 import json
diff --git a/DQMServices/Components/test/test_fastHaddMerge.py b/DQMServices/Components/test/test_fastHaddMerge.py
index 97dc8c2a2c417..993b69228f327 100644
--- a/DQMServices/Components/test/test_fastHaddMerge.py
+++ b/DQMServices/Components/test/test_fastHaddMerge.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Usage: test_fastHaddMerge.py [-t produce|check] [-n files]
 
diff --git a/DQMServices/Demo/test/dqmiodumpentries.py b/DQMServices/Demo/test/dqmiodumpentries.py
index 7d85ba71e48c4..c24c4329c23f8 100755
--- a/DQMServices/Demo/test/dqmiodumpentries.py
+++ b/DQMServices/Demo/test/dqmiodumpentries.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 import ROOT
 import argparse
 from collections import defaultdict
diff --git a/DQMServices/FileIO/python/DQM.py b/DQMServices/FileIO/python/DQM.py
index 70d9974ac0092..c4af24b897c37 100644
--- a/DQMServices/FileIO/python/DQM.py
+++ b/DQMServices/FileIO/python/DQM.py
@@ -1,4 +1,4 @@
-#!/bin/env python
+#!/bin/env python3
 
 from __future__ import print_function
 from builtins import range
diff --git a/DQMServices/FileIO/scripts/compareDQMOutput.py b/DQMServices/FileIO/scripts/compareDQMOutput.py
index 7c2baafc97104..90c1f1dfef44a 100755
--- a/DQMServices/FileIO/scripts/compareDQMOutput.py
+++ b/DQMServices/FileIO/scripts/compareDQMOutput.py
@@ -1,4 +1,4 @@
-#!/bin/env python
+#!/bin/env python3
 
 import os
 import sys
diff --git a/DQMServices/FileIO/scripts/compareHistograms.py b/DQMServices/FileIO/scripts/compareHistograms.py
index d1e663e306521..2e269da323a46 100755
--- a/DQMServices/FileIO/scripts/compareHistograms.py
+++ b/DQMServices/FileIO/scripts/compareHistograms.py
@@ -1,4 +1,4 @@
-#!/bin/env python
+#!/bin/env python3
 
 from __future__ import print_function
 import ROOT
diff --git a/DQMServices/FileIO/scripts/dqmMemoryStats.py b/DQMServices/FileIO/scripts/dqmMemoryStats.py
index b125270138ace..e64cf36847ad2 100755
--- a/DQMServices/FileIO/scripts/dqmMemoryStats.py
+++ b/DQMServices/FileIO/scripts/dqmMemoryStats.py
@@ -1,4 +1,4 @@
-#!/bin/env python
+#!/bin/env python3
 
 from __future__ import print_function
 import sys
diff --git a/DQMServices/FileIO/scripts/visDQMUpload.py b/DQMServices/FileIO/scripts/visDQMUpload.py
index 894c939019fea..a850f0421d71e 100755
--- a/DQMServices/FileIO/scripts/visDQMUpload.py
+++ b/DQMServices/FileIO/scripts/visDQMUpload.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 from __future__ import print_function
 import sys
diff --git a/DQMServices/FwkIO/scripts/DQMIO2histo.py b/DQMServices/FwkIO/scripts/DQMIO2histo.py
index a4f90c582a2a5..253fa3caac43e 100755
--- a/DQMServices/FwkIO/scripts/DQMIO2histo.py
+++ b/DQMServices/FwkIO/scripts/DQMIO2histo.py
@@ -1,4 +1,4 @@
-#!/bin/env python
+#!/bin/env python3
 
 """
 Script converting DQM I/O format input file into folder structured ROOT file.
diff --git a/DQMServices/StreamerIO/scripts/esMonitoring.py b/DQMServices/StreamerIO/scripts/esMonitoring.py
index b70eab8d84090..fb562bc1fd981 100755
--- a/DQMServices/StreamerIO/scripts/esMonitoring.py
+++ b/DQMServices/StreamerIO/scripts/esMonitoring.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 import argparse
 import subprocess
diff --git a/DQMServices/StreamerIO/scripts/personalPlayback.py b/DQMServices/StreamerIO/scripts/personalPlayback.py
index 604ce3ca2888a..ed622153fff38 100755
--- a/DQMServices/StreamerIO/scripts/personalPlayback.py
+++ b/DQMServices/StreamerIO/scripts/personalPlayback.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 from __future__ import print_function
 import os
diff --git a/DQMServices/StreamerIO/scripts/ztail.py b/DQMServices/StreamerIO/scripts/ztail.py
index 188f5b5b5b8d2..66b32a57e6bcc 100755
--- a/DQMServices/StreamerIO/scripts/ztail.py
+++ b/DQMServices/StreamerIO/scripts/ztail.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 import time
 import os
diff --git a/DQMServices/StreamerIO/scripts/ztee.py b/DQMServices/StreamerIO/scripts/ztee.py
index 313d2527f4edd..5f9c829ba2425 100755
--- a/DQMServices/StreamerIO/scripts/ztee.py
+++ b/DQMServices/StreamerIO/scripts/ztee.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 import argparse
 import subprocess