您需要将-v选项与brew outdated一起使用。
比较：

$ brew outdated | cat   
autoconf
automake

对比：

$ brew outdated -v | cat
autoconf (2.69) < 2.71
automake (1.16.2) < 1.16.5

但是，如果您计划对输出进行任何解析，则可能需要考虑--json选项：

$ brew outdated --json
{
  "formulae": [
    {
      "name": "autoconf",
      "installed_versions": [
        "2.69"
      ],
      "current_version": "2.71",
      "pinned": false,
      "pinned_version": null
    },
    {
      "name": "automake",
      "installed_versions": [
        "1.16.2"
      ],
      "current_version": "1.16.5",
      "pinned": false,
      "pinned_version": null
    },
...

有关详细信息，请使用brew help outdated。