Here're the broad strokes:
Line 2 will run an extra 70 minutes into the night.
Lines 1, 7, 8 and 9 will run an extra 80 minutes.
Lines 10 and 16 will run an extra 25 and 30 minutes, respectively, every day, not just Fri/Sat/day before holiday. In addition, Line 10 also gets an 80 minute Fri/Sat/day before holiday extension, coming to a 105 extra minutes on those days.
This doesn't always apply to the length of the line; for example, Line 7's extended operations halt at Qihua Road Station. Map below; grey areas are SOL.
They're also pledging to decrease the interval between trains during rush hour on weekdays, to ease congestion.
If you'd like a to-the-minute breakdown of exactly how late you can push your night out, you can check out Shanghai Metro's timetable right here (note the Line 16 and Line 9 times haven't been updated yet). They caution there might be hiccups as they implement the new schedules, and you're welcome to make your complaints known to the Shanghai Metro at 6437 0000, or on their WeChat channel shmetro.
And we'll just leave this here:
Mao Livehouse: Dapuqiao Station is 10 minutes walk. Last trains go 12.07am to Sheshan Station and 12.12am to Middle Yanggao Road.
Yuyintang: Zhongshan Park's 15 minutes away. Last trains are at 12.39am towards East Xujing and 12.17am towards Guanglan Road.
Bandai Namco Dream Hall (formerly QSW): Changshou Lu's 20 minutes away. Last trains go 12.28am towards Qihua Road and 12.15am towards Huamu Road.
The Pearl: North Sichuan Road's 5 minutes away. Last trains go 12.28am towards Xinjiang Wancheng and 12.09am towards Hongqiao Railway Station.
Mercedes-Benz Arena: China Art Museum's 5 minutes away. Last trains go 12.30am towards Shendu Highway and 12.15am towards Shiguang Road.