diff --git a/pyproject.toml b/pyproject.toml
index 43f8507..8c1ee61 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,11 +23,11 @@ keywords = ["vcard", "console", "addressbook"]
 license = {text = "GPL"}
 
 dependencies = [
-    "atomicwrites",
-    "configobj",
-    "ruamel.yaml",
-    "unidecode",
-    "vobject"
+    "atomicwrites == 1.4.1",
+    "configobj == 5.*, >= 5.0.6",
+    "ruamel.yaml >= 0.17.0",
+    "unidecode ~= 1.3.0",
+    "vobject == 0.9.6.1",
 ]
 
 [project.optional-dependencies]