diff --git a/requirements.txt b/requirements.txt
index 96c594b..ee95cdb 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,7 @@
-pyowm==2.10.0                   # weather
-Pillow==7.1.1                   # imaging
+pyowm>=2.10.0                   # weather
+Pillow>=7.1.1                   # imaging
 icalendar==4.0.6                # iCalendar parsing
 recurring-ical-events==0.1.16b0 # parse recurring events
 feedparser==5.2.1               # parse RSS-feeds
-numpy==1.18.2                   # image pre-processing
+numpy>=1.18.2                   # image pre-processing
+arrow>=0.15.6					# time operations
\ No newline at end of file