Planning the 2.37 release

Developers
1

It’s that time again!

With Stan 2.36 having come out in December, it’s time to start thinking about the next release. Graciously, @stevebronder has agreed to share some of the release duties with me going forward.

We are proposing the following dates:

  • Feature freeze on Tuesday[1], April 29th, 2025
  • Release on Tuesday, May 6th, 2025

As always, please use this thread if you have any thoughts on those dates, or if you need a pull request reviewed or think an issue is a high priority for this release. Pinging some usual suspects here: @mitzimorris @charlesm93 @spinkney @andrjohns

  1. Why Tuesday this time? Monday of that week is my birthday! ↩︎

2

For me, I have one set of features (sum_to_zero_matrix) I definitely want merged:

And a few general cleanups that would be nice:

3

I’d like to get the ILR simplex in that’s discussed in Save some memory in simplex constrain by WardBrian · Pull Request #3168 · stan-dev/math · GitHub.

I should put up a math issue for zero_sum_normal especially with the matrix version coming. Not sure this will get in this round though.

4

Does the ILR simplex make it easier to get a doubly-stochastic matrix? I assume we can use it for the row and column stochastic matrices

5

I have a parameterization of doubly stochastic matrices I’m working on. We need the sum to zero vector. I need a few quiet hours to finish it.

6

Because of the number of features currently in-flight and some personal travel I have coming up, @stevebronder and I are proposing new, delayed, dates for the freeze and release:

  • Feature freeze on Tuesday. May 27th, 2025
  • Release on Tuesday, June 3rd, 2025
7

FYI we are going to delay till later this week because we found a small bug in the Laplace implementation that needs to be fixed.

8

We hope to have the release candidates come out tomorrow morning. If anything new comes up we will probably wait until Monday to avoid it going into a weekend.