diff --git a/requirements.txt b/requirements.txt
index 887769c06..be2ff6ee0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -8,5 +8,5 @@ psutil                # for logging extra CPU-info
 colorhash             # for hashing a string into a color
 numpy                 # for computing median and other stats
 pytz                  # for timezone info
-tzlocal               # for figuring out the local timezone
+tzlocal==2.0          # for figuring out the local timezone; frozen to 2.0 because 3.0 conflicts the latest version of appscheduler (as of jan.2020)
 scipy                 # for statistical analysis of latency measurements