diff --git a/pyproject.toml b/pyproject.toml
index 5466afb1dfda6017dfc6a88228ab04aa6a96322d..0b6ba950763d38fc11892cb071eab46843b52a7a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -137,6 +137,7 @@ graphene-file-upload = "^1.3.0"
 django-countries = "^7.6.1"
 webdriver-manager = "^4.0.2"
 color-contrast = "^0.1.1"
+icalendar = "^6.1.0"
 
 [tool.poetry.extras]
 ldap = ["django-auth-ldap"]