Following commit a1d7884 on master branch, updates sparse .A to .toarray() as the former is deprecated in scipy 1.14

[afraser3]

I don't see other related issues in v2 besides this one line, but I fear I may have missed something. Alternatively (I know the goal is not to keep working on v2 but rather to encourage people upgrading to v3), could require scipy=1.13.1 in conda install script for v2.

[afraser3]

I wonder if this line also needs the same change. Admittedly I'm a bit out of my element here.