Add section on new discrete cell space to Migration guide

[pollockDeVis]

The migration guide is great for porting the older models. However, the migration guide is missing the new spaces introduced in Mesa-3. Could you please add that to the guide?

[EwoutH]

Thanks for reaching out! Do you mean the new Cell Space? That’s still experimental and in active development, and the old spaces are not deprecated in Mesa 3.0 yet, so they will keep being usable throughout the 3.x release cycle.

Once we stabilize the cell spaces and deprecate the current space, we will include it in the migration guide.

[quaquel]

If we follow the plan @EwoutH outlined in #2286, would it not make sense to include it in 3.0? By declaring the existing discrete spaces maintenance only in 3.0, we should stimulate users to shift to the new grid spaces. Having it in the migration guide might help with that.

[EwoutH]

Maintenance only does not mean unsupported, just that feature development is focused elsewhere.

But I don’t see harm in having a guide early. Let’s put it under the Mesa 3.1 section though.

[EwoutH]

For reference:

• New cell space
• Migration guide