I have a bottle of Agfa Rodinal which may be 4 years old. When I reorder a replacement, what is the equivalent?
4 y.o. could be Agfa Photo Rodinal or A&O Rodinal.

Replacement 1:1 can be:

R09 one shot/Rodinal CCP&S/Compard
Fomadon R09 NEW (Foma)
Adonal (Adox)

In fact all from the same manufacturer: CCP&S in Vaihingen - Enz, Germany. The old Agfa chemical plant.