A: Yes, the EVX-CEST software supports all EVX hand-helds (261, 264, 531). The difference is the number of channels (16 vs 32 vs 512). The software auto-detects this.
Her search history told the whole story.
If your organization has a Motorola Online account, you can purchase the CPS directly.
Motorola Solutions usually distributes this software through licensed dealers. You can find "Download Only" versions at retailers like Quality 2-Way Radios or Magnum Electronics . Motorola EVX261 - Commercial Radios - Wireless Solutions