Windows

Get-ChildItem -Filter "D10 *" | Rename-Item -NewName { $_.Name -replace '^D10', 'D8' }

What this does:

• Get-ChildItem -Filter “D10 *” grabs only files starting with D10
• Rename-Item renames them
• -replace '^D10', 'D8' swaps only the leading D10, not any later occurrences

To preview first, add -WhatIf:

Get-ChildItem -Filter "D10 *" | Rename-Item -NewName { $_.Name -replace '^D10', 'D8' } -WhatIf