I understand you're looking for a way to download DevExpress 15.2. Here are the legitimate options:
New Users: You must purchase a current subscription (such as Universal or DXperience) to gain access to all previous versions, including v15.2. devexpress 15.2 download
Important Note: DevExpress does not offer older versions for free. You must have a valid Universal, DXperience, or ASP.NET subscription that was active during the 15.2 lifecycle, or an active support plan that includes legacy download access. I understand you're looking for a way to
WinForms & WPF: New diagram controls and improved data grid performance. DevExpress 15
DevExpress Version Archive (subscription required)