Looks like Walnut Capital threw in the towel, and is selling the PAA building to Pitt. Honestly, not a bad fit, due to building layout and location.
I also want to highlight, although not directly related to development,
PPS has announced the start of a comprehensive redesign of its building footprint. No schools are yet targeted, but there will be substantial changes, as the district has stated an intention to move to entirely standalone middle schools (necessitating movement of a lot of students from existing K-8 or 6-12 buildings into new facilities), along with a reconfiguration of the magnet system to eliminate smaller programs with less interest, and presumably increase programs that often involve waitlisting.
In the past, the city has shown a willingness to close schools based upon prospective real estate value rather than academic performance, to maximize return for the district. Witness closing the Reizenstein Middle School (which paved the way for the second phase of Bakery Square) or the conversion of Schenley High School into apartments. In contrast, a lot of shuttered schools in more troubled neighborhoods have been vacant for over a decade, with little interest unless a private school buys it, or funding can be found to convert it into housing.
I will say straight off the bat Montessori K-5 will be closed in its current facility. The school is very popular and well regarded, but the building is in terrible condition, and needs millions in asbestos remediation. The students and teachers will be moved to a vacant school elsewhere in the East End (perhaps Linden K-5 or Sterrett 6-8, both of which are likely to close) and they'll try and sell off the building to a private developer for apartments (which the market can bear there, provided NIMBYs don't get in the way).
The more interesting case though is Arsenal in Central Lawrenceville. The elementary school is at about half capacity, mostly filled up with kids from Garfield these days, which has lacked a neighborhood school for around the last decade. The middle school is only at 25% capacity. If they are serious about ending K-8 schools, moving the middle school kids out of Sunnyside K-8 in Stanton Heights will mean more than enough space for Garfield's elementary students there (It's actually closer to most of them), with Central Lawrenceville's few neighborhood students either following suit or going into Woolslair. Then the district could make a dedicated middle school somewhere else in the upper East End (I'd say Lincoln K-5 in Larimer would be the most centrally located), which frees up the entirety of Arsenal for redevelopment, as they would undoubtedly get a good deal of money for a building already laid out well for residential conversion, where a new wing could be constructed fronting directly on Butler Street.
There's a ton of awful messes to deal with elsewhere of course, but going into all that goes way beyond the purposes of this thread.