diff --git a/INSTALL.ubuntu.md b/INSTALL.ubuntu.md
index d5ca0d2..495e328 100644
--- a/INSTALL.ubuntu.md
+++ b/INSTALL.ubuntu.md
@@ -154,6 +154,7 @@ sudo apt install python3-pip
 python3 -m pip install python-dotenv;
 python3 -m pip install psycopg2-binary;
 python3 -m pip install json5;
+python3 -m pip install stdiomask;
 python3 -m pip install requests;
 ```
 
diff --git a/INSTALL.windows.md b/INSTALL.windows.md
index 3ae8ea2..c7f18cf 100644
--- a/INSTALL.windows.md
+++ b/INSTALL.windows.md
@@ -54,6 +54,7 @@ When output matches mempool.space, BTC Core synced.
 py -m pip install python-dotenv
 py -m pip install pyscopg2-binary
 py -m pip install json5
+py -m pip install stdiomask
 py -m pip install requests
 ```