Please edit this tracker as necessary

Below a list of deprecations by kind and scipy release. Ideally all deprecations should come with an announced behaviour change, and with an announced timeframe (i.e. SciPy version where things will be changed/removed), and other items migrated there as appropriate.

In most cases, we aim for removal/behaviour change one year after a given deprecation is introduced in 1.N (not just in documentation, but in a way that the user cannot miss, i.e. raise DeprecationWarning upon use). Due to the 6 month release cadence this often ends up being 1.(N+2), but exceptional out-of-band releases can occur, so try to avoid promising exact versions. For more disruptive cases, adaptations (e.g. longer timeframes) can be made as necessary.

Cleaning up the past

Deprecations in documentation only

None currently tracked, if you find one, let us know!

Deprecated without announced removal

None currently tracked, if you find one, let us know!

Removal announced, missed

• 1.5 (announced removal for 1.7)
  • ENH: special: extend nbdtr and friends for float n instead of truncation #15596
• 1.9 (announced removal for 1.11)
  • DEP: remove deprecated linprog-methods #15707

In progress for upcoming release

Old deprecations, warning sharpened for removal in 1.19/2.0

None so far.

New deprecations

• DEP: deprecate positional arguments for signatures being changed in current cycle (rolling) #18703
• DEP: stats: deprecate tiecorrect #25564
• MAINT/DEP: linalg: deprecate remaining lwork arguments in linalg #25617
• DEP: stats.mstats: deprecate functions, namespace, and other uses of MaskedArray in stats #26018

Removal announced for 1.19

• Remove old dtype handling from sparse.diags{,_array} (follow-up to this)
• Don't ravel multidimensional inputs (follow-up to this)
• Remove precenter (follow-up to this)
• Remove scipy.odr (follow-up to this)

Removal announced/planned for 2.0

• all private modules affected by Making clearer what namespaces are public by use of underscores #14360 / DEP: extend deprecation of private namespaces also to fortran-generated modules #19907 -- see DEP: remove private but present modules ready for SciPy 2.0 #25595
• remove scipy.misc (follow-up to this) -- see DEP: banish scipy.misc #25711

Scheduled removals in future versions

Removal announced for 1.20/2.1

• 1.18
  • Remove py_vq (follow-up to this)
  • reject column vector input to {r}matvec (follow-up to this)
  • Remove pade, lagrange, approximate_taylor_polynomial (follow-up to this)
  • Remove lwork argument to linalg.qr) (follow-up to this)
  • Switch the default output type of kron, kronsum, block_diag, tril, triu (follow-up to this)
  • DEP: io: deprecate default spmatrix kwargs values (follow-up to this)
  • Raise for non-lapack dtypes (follow-up of this)

Removal announced for 2.2.0

• 2.0.0
  • Remove stats.tiecorrect (follow-up to this)
  • Remove remaining lwork arguments (follow-up to this)

Removal announced for 2.4.0

• 2.0.0
  • Remove stats.mstats (follow-up to this)

Other

Outstanding deprecations

List most likely incomplete

• Deprecation of scipy.spatial.kdtree distance functions #10419
• DEP: sparse.spmatrix: deprecate todense #14494
• DEP: stats: deprecate support for _rvs using _random_state. #15924
• ENH/DEP: stats.find_repeats/tiecorrect/etc.: add array API support or deprecate?  #21077
• DEP: io.mmread: deprecate extreme precision values #19949

Outstanding behaviour changes

List incomplete (and intentionally so; not every tiny planned change needs to be here from the get go; but do add it if desired, ideally already above with a direct action item).

• Filter design functions should accept other input than TF. #3259
• Sparse: document and test handling of explicit zeros #3343
• Support binary operators on binary sparse matrices #3590
• scipy.sparse Unexpected behaviour for numpy.dot(sparse,dense) and no support for output array #4063 / wishlist: sparse in-place AXPY/GEMM instead of deprecated sparsetools.csc_matvecs #5348
• numpy and scipy qr have different mode names. #4818
• scipy.signal needs a unified filter API #6137
• remove KDTree Python implementation #8923
• API: Inconsistent naming of arguments in svd / svds / eig / eigs #11334
• Hamming distance returns unexpected value for string comparisons #11991
• ENH: add more aka for cdist/pdist #14039
• ENH: refactor RNG usage to use np.random.Generator #14322
• Tolerance arguments for scipy.sparse.linalg.{lsmr,lsqr} do not match related functions #19704

Reference

Closed but relevant for continued maintenance

• API: keywords only arguments #14714