RC Phone app for Windows/Mac, version 19.4x download

Hi! I have a US account and am using RingCentral Phone to mass text people. Now that we're working from home, we are running into issues with our existing staff mass texting prospects and clients but having all texts create a giant group text, with no option to send an individual text to all people. We are currently using version history 20.x, but we have had success using version 19.4 of the phone app in our workplace and have had no issues mass texting to individuals with that version. Is there any place we can get a download link for Windows and Mac phone app version 19.4 for me to send to my staff? Thanks for your help!