In 4.0 the JSDoc tag @deprecated is added to the type system. You can use @deprecated anywhere you can use JSDoc currently.

interface AccountInfo {
  name: string;
  gender: string;

  /** @deprecated use gender field instead */
  sex: "male" | "female";
}

declare const userInfo: AccountInfo;
userInfo.sex;

// TypeScript will offer a non-blocking warning when a deprecated property is accessed, and editors like vscode will use show the deprecated info in places like intellisense, outlines and in your code.