Jekyll Collections not sorting by date

[shushugah]

Describe the bug
In both the default and manually specified sortable_fields: ['fields.date'], the collection (events) is sorted by their file name and not their front matter date. This is the repository https://github.com/techworkersco/twc-site-berlin, and the admin-configs

In either situation, the files "sorted" by date, show collection of events 1.md, 10.md, 11.md, 2.md, 21.md etc..

Expected behavior
I'd expect that the date column is used to sort the files

[erezrokah]

Hi @shushugah I believe this is a duplicate of #4637.

You should use ISO format for the dates in order for the sort to treat them as dates and not strings (until that issue is resolved).
See https://raw.githubusercontent.com/netlify/netlify-cms/master/website/content/blog/netlify-cms-2-4-0.md

Closing, please comment if you have additional questions