Upgrade to 1.17 failed

[phenomlab]

Attempted to upgrade to 1.17 this morning, and am now left with an instance that won't start

Below is the log

2021-04-22T08:57:53.289Z [4567/355660] - info: [plugins/spam-be-gone] Settings loaded
2021-04-22T08:57:53.299Z [4567/355660] - warn: [sso-discord-alt] Missing sso-discord-alt configuration. Not enabling authentication strategy.
2021-04-22T08:57:53.314Z [4567/355660] - info: [api] Adding 1 route(s) to `api/v3/plugins`
2021-04-22T08:57:53.325Z [4567/355660] - info: [router] Routes added
2021-04-22T08:57:53.329Z [4567/355660] - info: NodeBB Ready
2021-04-22T08:57:53.330Z [4567/355660] - info: Enabling 'trust proxy'
2021-04-22T08:57:53.332Z [4567/355660] - info: NodeBB is now listening on: 0.0.0.0:4567
2021-04-22T08:57:53.563Z [4567/355660] - error: /admin/dashboard
TypeError: Cannot read property 'length' of undefined
    at module.getObjectsFields (/home/phenomlab/nodebb/src/database/mongo/hash.js:123:15)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async User.getUsersFields (/home/phenomlab/nodebb/src/user/data.js:67:17)
    at async User.getUsersData (/home/phenomlab/nodebb/src/user/data.js:141:10)
    at async User.getUserData (/home/phenomlab/nodebb/src/user/data.js:136:17)
    at async getLastRestart (/home/phenomlab/nodebb/src/controllers/admin/dashboard.js:235:19)
    at async Promise.all (index 3)
    at async dashboardController.get (/home/phenomlab/nodebb/src/controllers/admin/dashboard.js:21:64)
    at async /home/phenomlab/nodebb/src/routes/helpers.js:61:5
2021-04-22T08:57:53.590Z [4567/355660] - error: uncaughtException: Cannot read property 'length' of undefined
TypeError: Cannot read property 'length' of undefined
    at module.getObjectsFields (/home/phenomlab/nodebb/src/database/mongo/hash.js:123:15)
    at Object.wrapperCallback [as getObjectsFields] (/home/phenomlab/nodebb/src/promisify.js:46:11)
    at User.getUsersFields (/home/phenomlab/nodebb/src/user/data.js:67:26)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async User.getUsersData (/home/phenomlab/nodebb/src/user/data.js:141:10)
    at async User.getUserData (/home/phenomlab/nodebb/src/user/data.js:136:17)
    at async Promise.all (index 4)
    at async Object.renderHeader (/home/phenomlab/nodebb/src/middleware/header.js:72:18)
    at async renderHeaderFooter (/home/phenomlab/nodebb/src/middleware/render.js:99:10)
    at async Promise.all (index 0) {"error":{},"stack":"TypeError: Cannot read property 'length' of undefined\n    at module.getObjectsFields (/home/phenomlab/nodebb/src/database/mongo/hash.js:123:15)\n    at Object.wrapperCallback [as getObjectsFields] (/home/phenomlab/nodebb/src/promisify.js:46:11)\n    at User.getUsersFields (/home/phenomlab/nodebb/src/user/data.js:67:26)\n    at processTicksAndRejections (node:internal/process/task_queues:96:5)\n    at async User.getUsersData (/home/phenomlab/nodebb/src/user/data.js:141:10)\n    at async User.getUserData (/home/phenomlab/nodebb/src/user/data.js:136:17)\n    at async Promise.all (index 4)\n    at async Object.renderHeader (/home/phenomlab/nodebb/src/middleware/header.js:72:18)\n    at async renderHeaderFooter (/home/phenomlab/nodebb/src/middleware/render.js:99:10)\n    at async Promise.all (index 0)","exception":true,"date":"Thu Apr 22 2021 09:57:53 GMT+0100 (British Summer Time)","process":{"pid":355660,"uid":1000,"gid":1000,"cwd":"/home/phenomlab/nodebb","execPath":"/usr/bin/node","version":"v16.0.0","argv":["/usr/bin/node","/home/phenomlab/nodebb/app.js"],"memoryUsage":{"rss":295014400,"heapTotal":193429504,"heapUsed":162141056,"external":74595732,"arrayBuffers":71168333}},"os":{"loadavg":[1.18,0.67,0.47],"uptime":238331.53},"trace":[{"column":15,"file":"/home/phenomlab/nodebb/src/database/mongo/hash.js","function":"module.getObjectsFields","line":123,"method":"getObjectsFields","native":false},{"column":11,"file":"/home/phenomlab/nodebb/src/promisify.js","function":"Object.wrapperCallback [as getObjectsFields]","line":46,"method":"wrapperCallback [as getObjectsFields]","native":false},{"column":26,"file":"/home/phenomlab/nodebb/src/user/data.js","function":"User.getUsersFields","line":67,"method":"getUsersFields","native":false},{"column":5,"file":"node:internal/process/task_queues","function":"processTicksAndRejections","line":96,"method":null,"native":false},{"column":10,"file":"/home/phenomlab/nodebb/src/user/data.js","function":"async User.getUsersData","line":141,"method":"getUsersData","native":false},{"column":17,"file":"/home/phenomlab/nodebb/src/user/data.js","function":"async User.getUserData","line":136,"method":"getUserData","native":false},{"column":null,"file":null,"function":"async Promise.all","line":null,"method":"all","native":false},{"column":18,"file":"/home/phenomlab/nodebb/src/middleware/header.js","function":"async Object.renderHeader","line":72,"method":"renderHeader","native":false},{"column":10,"file":"/home/phenomlab/nodebb/src/middleware/render.js","function":"async renderHeaderFooter","line":99,"method":null,"native":false},{"column":null,"file":null,"function":"async Promise.all","line":null,"method":"all","native":false}]}
2021-04-22T08:57:53.591Z [4567/355660] - error: TypeError: Cannot read property 'length' of undefined
    at module.getObjectsFields (/home/phenomlab/nodebb/src/database/mongo/hash.js:123:15)
    at Object.wrapperCallback [as getObjectsFields] (/home/phenomlab/nodebb/src/promisify.js:46:11)
    at User.getUsersFields (/home/phenomlab/nodebb/src/user/data.js:67:26)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async User.getUsersData (/home/phenomlab/nodebb/src/user/data.js:141:10)
    at async User.getUserData (/home/phenomlab/nodebb/src/user/data.js:136:17)
    at async Promise.all (index 4)
    at async Object.renderHeader (/home/phenomlab/nodebb/src/middleware/header.js:72:18)
    at async renderHeaderFooter (/home/phenomlab/nodebb/src/middleware/render.js:99:10)
    at async Promise.all (index 0)
2021-04-22T08:57:53.591Z [4567/355660] - info: [app] Shutdown (SIGTERM/SIGINT) Initialised.
2021-04-22T08:57:53.592Z [4567/355660] - info: [app] Web server closed to connections.
2021-04-22T08:57:53.592Z [4567/355660] - info: [app] Live analytics saved.
2021-04-22T08:57:53.602Z [4567/355660] - info: [app] Database connection closed.
2021-04-22T08:57:53.602Z [4567/355660] - info: [app] Shutdown complete.
3 restarts in 10 seconds, most likely an error on startup. Halting.

Help !!

[phenomlab]

@phenomlab Seems to be an incompatible plugin. Disabled them all, and NodeBB started. Working my way through to find the culprit.

[phenomlab]

Not a pretty site over at https://phenomlab.com. NodeBB is up, and the widget-essentials plugin is installed and active, but doesn't work. This means my customised theme and layout is completely broken.

[phenomlab]

Ok. Cache issue. Cleared cache, and back in play (almost)