diff --git a/.travis.yml b/.travis.yml
index 6e71156..9632b79 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,7 +15,7 @@ matrix:
       env:
         - TEST_SUITE="tests/uts/test_client.py"
     - stage: agent unit tests
-      python: 2.7
+      python: 3.5
       env:
         - TEST_SUITE="tests/uts/test_agent.py"
     - stage: integration tests
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a4b2702..e8d5ba0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Changed
+- upgrade agent to run with python3
 
 ## [1.8.6] - 2019-11-05
 ### Added
diff --git a/talker_agent/Dockerfile b/talker_agent/Dockerfile
index a93aa7e..027048c 100644
--- a/talker_agent/Dockerfile
+++ b/talker_agent/Dockerfile
@@ -1,4 +1,4 @@
-FROM python:2.7-slim-buster
+FROM python:3.5-slim-buster
 
 #args from docker-compose.yaml
 ARG TALKER_AGENT_VERSION
diff --git a/talker_agent/talker.py b/talker_agent/talker.py
index 580e1da..189376b 100644
--- a/talker_agent/talker.py
+++ b/talker_agent/talker.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/local/bin/python3
 
 
 """
@@ -304,7 +304,7 @@ def start(self):
                         time.sleep(random.random() * 2)
                         continue
 
-                self.stderr.chunks.append(e.strerror)
+                self.stderr.chunks.append(e.strerror.encode('utf-8'))
                 self.set_result(e.errno)
                 self.finalize()
                 return
diff --git a/tests/integration/test_sanity.py b/tests/integration/test_sanity.py
index 112939d..7378c2c 100644
--- a/tests/integration/test_sanity.py
+++ b/tests/integration/test_sanity.py
@@ -1,7 +1,7 @@
 import unittest
 
 from talker_agent.talker import Config
-from talker.errors import CommandAbortedByOverflow
+from talker.errors import CommandAbortedByOverflow, CommandExecutionError
 from tests.utils import get_talker_client, get_retcode, get_stdout
 
 
@@ -38,3 +38,8 @@ def test_max_output_per_channel_set(self):
             if expected_ret == 0:
                 res = get_stdout(self.client.redis, cmd.job_id)
                 self.assertEqual(res, val)
+
+    def test_bad_command(self):
+        cmd = self.client.run(self.host_id, 'foo')
+        with self.assertRaises(CommandExecutionError):
+            cmd.result()