diff --git a/dev-docs/bidders/indexExchange.md b/dev-docs/bidders/indexExchange.md
index 5ed73f868a..7b4b30f128 100644
--- a/dev-docs/bidders/indexExchange.md
+++ b/dev-docs/bidders/indexExchange.md
@@ -305,6 +305,27 @@ pbjs.setConfig({
 });
 ```
 
+#### The **detectMissingSizes** feature
+With a recent update, the IX bid adapter bids on all banner sizes available in an ad unit, if IX is configured for at least one banner size in that ad unit. This default behavior if not required, can be turned off by using the `detectMissingSizes` flag.
+```
+pbjs.setConfig({
+                ix: {
+                    detectMissingSizes: false
+                }
+            });
+```
+OR
+```
+pbjs.setBidderConfig({
+                bidders: ["ix"],
+                config: {
+                    ix: {
+                        detectMissingSizes: false
+                    }
+                }
+            });
+```
+
 ### 2. Include `ixBidAdapter` in your build process
 
 When running the build command, include `ixBidAdapter` as a module, as well as `dfpAdServerVideo` if you require video support.