diff --git a/dev-requirements.txt b/dev-requirements.txt
index 9f085adb5..35892f90b 100644
--- a/dev-requirements.txt
+++ b/dev-requirements.txt
@@ -23,7 +23,7 @@ bcrypt==4.2.1
     # via modoboa (pyproject.toml)
 black==25.1.0
     # via modoboa (pyproject.toml)
-caldav==1.3.9
+caldav==1.4.0
     # via modoboa (pyproject.toml)
 certifi==2025.1.31
     # via requests
diff --git a/ldap-requirements.txt b/ldap-requirements.txt
index add885c87..e8206872b 100644
--- a/ldap-requirements.txt
+++ b/ldap-requirements.txt
@@ -19,7 +19,7 @@ attrs==25.1.0
     #   referencing
 bcrypt==4.2.1
     # via modoboa (pyproject.toml)
-caldav==1.3.9
+caldav==1.4.0
     # via modoboa (pyproject.toml)
 certifi==2025.1.31
     # via requests
diff --git a/mysql-requirements.txt b/mysql-requirements.txt
index 46b832e72..c4a6af651 100644
--- a/mysql-requirements.txt
+++ b/mysql-requirements.txt
@@ -19,7 +19,7 @@ attrs==25.1.0
     #   referencing
 bcrypt==4.2.1
     # via modoboa (pyproject.toml)
-caldav==1.3.9
+caldav==1.4.0
     # via modoboa (pyproject.toml)
 certifi==2025.1.31
     # via requests
diff --git a/postgresql-requirements.txt b/postgresql-requirements.txt
index 62f3cd85d..70ed5686e 100644
--- a/postgresql-requirements.txt
+++ b/postgresql-requirements.txt
@@ -19,7 +19,7 @@ attrs==25.1.0
     #   referencing
 bcrypt==4.2.1
     # via modoboa (pyproject.toml)
-caldav==1.3.9
+caldav==1.4.0
     # via modoboa (pyproject.toml)
 certifi==2025.1.31
     # via requests
diff --git a/pyproject.toml b/pyproject.toml
index 203d00998..a733fc2c2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -79,7 +79,7 @@ dependencies = [
         # User
         "drf-nested-routers",
         "vobject",
-        "caldav==1.3.9"
+        "caldav==1.4.0"
 ]
 [project.optional-dependencies]
 dev = [
diff --git a/requirements.txt b/requirements.txt
index b1231aaee..037334001 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -19,7 +19,7 @@ attrs==25.1.0
     #   referencing
 bcrypt==4.2.1
     # via modoboa (pyproject.toml)
-caldav==1.3.9
+caldav==1.4.0
     # via modoboa (pyproject.toml)
 certifi==2025.1.31
     # via requests
diff --git a/test-requirements.txt b/test-requirements.txt
index cfb7936b5..334370db7 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -25,7 +25,7 @@ bcrypt==4.2.1
     # via modoboa (pyproject.toml)
 cachetools==5.5.1
     # via tox
-caldav==1.3.9
+caldav==1.4.0
     # via modoboa (pyproject.toml)
 certifi==2025.1.31
     # via requests