Drupal 8 version

I do but there is no timeline for it at this point.

would be great! any news here?

A couple of random thoughts about this.

Constraints:
- A multifield can only host fields with cardinality != -1. For now let's assume that it can only host fields with cardinality = 1.
- A multifield is considered revisionable, if any of the guest fields are revisionable.
- A multifield is considered translatable, if any of the guest fields are translatable.
- Changes to a multifiled definition are locked when there is field data already present.

Implementation quirks:
- Revisions and translations are handled at the host field level.
- Adding, removing or updating guest fields should trigger an entity definition update since the table layout may change.
- Constraints on the guest fields need to bubble up to the host field.
- Multifields should not be used as base fields, instead declare any base fields directly.

Looking forward to the drupal 8 version :)

@e0ipso: "A multifield can only host fields with cardinality != -1. For now let's assume that it can only host fields with cardinality = 1." Yep, the latter is the requirement with the D7 code too.

Perhaps it would be best to combine forces with Complex Field? They look like they already have a head start.

#2784931: Proposal: Deprecate Field Collections for Drupal 8, focus on Entity Reference Revisions & Paragraphs

As much as I love Field collection, it still has to save actual entities, and can cause performance problems due to having to load all the referenced field collection entities on node, or parent entity load.

Paragraphs can be different.

We also have a pending issue that would significantly improve the situation:
- making paragraphs save more specific.
- Reintroduce render cache for paragraphs. We disabled them recently because it was redundant and made Paragraphs slow instead of helping.

Once those issues are resolved, the quote should no more apply. Not also, Paragraphs offers edit mode settings that allow nests to be closed by default, needing an "edit" button click. This can also reduce loading amount of elements on edit.

Plus we have many issues that are discussing how we can improve this UX for editing highly nested situations.

Given that there have been no opposing efforts in the last 2 years, let's update the project page stating that the module has been deprecated in Drupal 8 in favour of Paragraphs.

Paragraphs can not be considered as a real D8 port, due different data structure.

Lullabot's rich field module is much closer. You can see it in action here:
https://youtube.com/watch?v=RyMN1n8r4VE

I hope they will release it..

https://gitlab.com/hawkeye.twolf/rich_field
https://www.drupal.org/project/field_union

see #607396: Killer feature: Fieldable Fields in core (with updated issue description)

FlexField module is good alternative to MultiField for Drupal 8.x, if we need simple fields in group.