Plugin needs update

Error when trying to install plugin:

Error while compiling: DiscordAuth.cs(148,33): error CS0246: The type or namespace name `Snowflake' could not be found. Are you missing an assembly reference?

Found this in the main .cs:
[JsonProperty(PropertyName = "Discord Server ID (Optional if bot only in 1 guild)")]
public Snowflake GuildId { get; set; }

private class Data
public Hash<string, Snowflake> Players = new Hash<string, Snowflake>();

public IDictionary<string, Snowflake> GetSteamToDiscordIds()
return data.Players;

The main discord extension was installed.
I am using other discord plugins like discord chat /discord messages and they work fine.