diff --git a/README.md b/README.md
index 506f0988..32e51da5 100644
--- a/README.md
+++ b/README.md
@@ -200,6 +200,15 @@ For additional details please refer to [xo/dburl](https://github.com/xo/dburl) d
 
 ## Miscellaneous
 
+<details>
+<summary>Handling NULL values</summary>
+
+Queries that return `NULL` values are supported, but they are not rendered as metrics. It's useful for situations, when
+the result set depends on some conditions, so it may be empty. Whenever a query returns `NULL` values, the exporter
+logs a message at the `Debug` level. If your query constantly returns `NULL` values, it most likely means that you need
+to revisit your query logic.
+</details>
+
 <details>
 <summary>Multiple database connections</summary>
 
diff --git a/VERSION b/VERSION
index 66333910..249afd51 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.18.0
+0.18.1