The NYPD has to scrap the 36,000 smartphones it gave cops over the past two years because they’re already obsolete and can’t be upgraded, The Post has learned. The city bought Microsoft-based Nokia smartphones as part of a $160 million NYPD Mobility Initiative that Mayor Bill de Blasio touted as “a huge step into the 21st century.” But just months after the last phone was handed out, officials plan to begin replacing them all with brand-new iPhones by the end of the year, sources said.