diff --git a/intervals/deciphon_intervals/__init__.py b/intervals/deciphon_intervals/__init__.py
index cab2d7e..37d6bca 100644
--- a/intervals/deciphon_intervals/__init__.py
+++ b/intervals/deciphon_intervals/__init__.py
@@ -91,7 +91,7 @@ class RInterval(Interval):
 
     @model_validator(mode="before")
     def pre_root(cls, values: dict[str, Any]) -> dict[str, Any]:
-        assert values["start"] <= values["stop"]
+        assert values["start"] <= values["stop"] + 1
         return values
 
     @property
diff --git a/intervals/pyproject.toml b/intervals/pyproject.toml
index d771f77..4d5f8e6 100644
--- a/intervals/pyproject.toml
+++ b/intervals/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "deciphon-intervals"
-version = "0.1.0"
+version = "0.1.1"
 description = "It helps to model the Python and R intervals seamlessly."
 authors = ["Danilo Horta <danilo.horta@pm.me>"]
 license = "MIT"