Are they not on the progdvb web site?
They do have old versions available for download there.
Unfortunately, older versions do not.
There is only these versions ;
ProgDVB 6.61.1 x32 Pro Last version using ProgDVB Engine 4.x. Support hardmode and some other oldest functions
ProgDVB 6.61.1 x32 Std
ProgDVB 6.61.1 x64 Pro
ProgDVB 6.61.1 x64 Sdt
ProgDVB 5.16.2 Pro(full install). last version using ProgDVB Engine 2.x.
ProgDVB 5.16.2 Std(full install). last version using ProgDVB Engine 2.x.
ProgDVB 5.09.2 (full install). last version using ProgDVB Engine 1.x.
ProgDVB 4.92.4 Pro(full install). last 4.x version.
ProgDVB 4.92.4 Std(full install). last 4.x version.
ProgDVB 4.91.8 (full install). last version for Windows 9x.
ProgDVB 4.85.3 (full install). last version using ProgDVB Engine 1.x.
ProgDVB 4.62.6 (full install). last version that supports only one device at a time.
ProgDVB 4.56.2 (full install). last version not based on ProgDvb engine.
ProgDVB 4.48.2 (full install). last not Unicode version.
ProgDVB 4.38.6 test (full install).
ProgDVB 4.26.4 (full install [English/Russian]).
ProgDVB 4.07
ProgDVB 3.31.1
ProgDVB 2.07.1
ProgDVB 1.76