diff --git a/doc/python/choropleth-maps.md b/doc/python/choropleth-maps.md
index 8a61b1e666..ade5d2a4bc 100644
--- a/doc/python/choropleth-maps.md
+++ b/doc/python/choropleth-maps.md
@@ -52,7 +52,7 @@ Making choropleth maps requires two main types of input:
 
 The GeoJSON data is passed to the `geojson` argument, and the data is passed into the `color` argument of `px.choropleth` (`z` if using `graph_objects`), in the same order as the IDs are passed into the `location` argument.
 
-**Note** the `geojson` attribute can also be the URL to a GeoJSON file, which can speed up map rendering in certain cases.
+**Note** the `geojson` attribute can also be the URL to a GeoJSON file, which can speed up map rendering in certain cases. Note also that Plotly requires that the GeoJSON file format follows the 2008 specification, which is **not** the latest one.
 
 ### Choropleth Map with plotly.express
 
diff --git a/doc/python/mapbox-county-choropleth.md b/doc/python/mapbox-county-choropleth.md
index 5fa40aef6b..d96b710f38 100644
--- a/doc/python/mapbox-county-choropleth.md
+++ b/doc/python/mapbox-county-choropleth.md
@@ -51,7 +51,7 @@ Making choropleth Mapbox maps requires two main types of input:
 
 The GeoJSON data is passed to the `geojson` argument, and the data is passed into the `color` argument of `px.choropleth_mapbox` (`z` if using `graph_objects`), in the same order as the IDs are passed into the `location` argument.
 
-**Note** the `geojson` attribute can also be the URL to a GeoJSON file, which can speed up map rendering in certain cases.
+**Note** the `geojson` attribute can also be the URL to a GeoJSON file, which can speed up map rendering in certain cases. Note also that Plotly requires that the GeoJSON file format follows the 2008 specification, which is **not** the latest one.
 
 #### GeoJSON with `feature.id`