Update 'README.md'

README.md

@@ -34,12 +34,14 @@ silentdragonlite does automatic note and utxo management, which means it doesn't
 
 | Linux Version | Rust Version Tested | Command to install  |
 |---------------|--------|---------------------------|
+| Ubuntu 18.04  | 1.65.0 | [USE RUSTUP](https://www.rust-lang.org/tools/install) |
 | Ubuntu 20.04  | 1.57.0 | sudo apt install rust-all |
 | Debian 11     | 1.50.0 | [USE RUSTUP](https://www.rust-lang.org/tools/install) |
 | Arch Linux    | 1.56.0 | pacman -S rustc cargo     |
 
 * Debian 11 comes with a much older rust compiler (1.48.0) and so you want to use rustup with Debian and install at least 1.50.0.
 * If you're using another Linux distro, then consult their package manager for rustc and cargo, but if it's tool old then you want to [use Rustup](https://www.rust-lang.org/tools/install) to install at least 1.50.0.
+* The build will fail if you do not have `rustfmt` binary, which is included when you use `rustup` but may not be included in via operating system packages. Using `rustup` is recommended
 
 #### The compilation