A: No. Microsoft no longer hosts it on official download servers. The last official inclusion was in Windows XP SP3 and Windows Server 2003. Even if you find a copy on a third-party site (like oldversion.com), it is insecure and unsupported.
Important: Jet OLEDB 4.0 is an older data access provider included with Microsoft Data Access Components (MDAC) and historically shipped with Windows and Office. It is not provided separately as a modern Microsoft download for newer Windows versions; on 64-bit systems Microsoft Jet 4.0 is unsupported for 64-bit processes. For modern development use Microsoft Access Database Engine (ACE) or other supported providers.
If you still need Jet OLEDB 4.0 (for a 32-bit app on a supported OS), follow these steps.
Microsoft Jet OLE DB 4.0 is deprecated and is not available as a standalone download for current versions of Windows.
This is the official replacement for Jet OLEDB 4.0. It supports:
Where to download: Go directly to Microsoft Download Center and search for:
"Microsoft Access Database Engine 2016 Redistributable"
Or use this direct link pattern (ensure it points to microsoft.com):
https://www.microsoft.com/en-us/download/details.aspx?id=54920
Connection string example (modern replacement):
Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Data\Northwind.mdb;Persist Security Info=False;