diff --git a/.tool-versions b/.tool-versions
new file mode 100644
index 0000000..2ddd340
--- /dev/null
+++ b/.tool-versions
@@ -0,0 +1,2 @@
+flutter 2.2.1
+cmake 3.20.4
diff --git a/README.md b/README.md
index e398240..688df9b 100644
--- a/README.md
+++ b/README.md
@@ -13,10 +13,14 @@ build requirements:
 * git
 * autotools
 
-install flutter:
+install flutter with snap:
 
     $ sudo snap install flutter --classic
 
+or with [asdf](https://github.com/asdf-vm/asdf):
+
+    $ asdf install
+
 a one liner to install everything else:
 
     $ sudo apt install make automake libtool pkg-config cmake git