diff --git a/README.md b/README.md
index 6dc2859..fdaed8f 100644
--- a/README.md
+++ b/README.md
@@ -172,7 +172,7 @@ class MyEntity implements RevisionableInterface
         return $this;
     }
 
-    public function getRevision(): RevisionInterface
+    public function getRevision(): ?RevisionInterface
     {
         return $this->revision;
     }
diff --git a/UPGRADE-2.0.md b/UPGRADE-2.0.md
index b484e4f..1638f82 100644
--- a/UPGRADE-2.0.md
+++ b/UPGRADE-2.0.md
@@ -15,7 +15,7 @@ UPGRADE FROM 1.x to 2.0
   `RevisionFactoryInterface`. Any implementation of these interfaces must add
   matching return types:
   - `RevisionableInterface::setRevision()`: `static` (now fluent, must `return $this;`)
-  - `RevisionableInterface::getRevision()`: `RevisionInterface`
+  - `RevisionableInterface::getRevision()`: `?RevisionInterface`
   - `RevisionInterface::getUser()`: `?string`
   - `RevisionInterface::getCreatedAt()`: `\DateTimeInterface`
   - `RevisionFactoryInterface::createRevision()`: `RevisionInterface` (no longer
diff --git a/src/RevisionableInterface.php b/src/RevisionableInterface.php
index 7f63769..2eea3aa 100644
--- a/src/RevisionableInterface.php
+++ b/src/RevisionableInterface.php
@@ -14,7 +14,7 @@ interface RevisionableInterface
     public function setRevision(RevisionInterface $revision): static;
 
     /**
-     * Return the current revision
+     * Return the current revision, or null if there is none.
      */
-    public function getRevision(): RevisionInterface;
+    public function getRevision(): ?RevisionInterface;
 }