This may be a change, but in the instructions my meter specifies the 357 battery.
Radio Shack has a 357 or LR44 which is a 1.5V Silver Oxide.
The battery packet says that it also replaces the alkaline batteries of the same dimension.
Andreas and PE, many thanks for the input.
It would appear that there has been a change regarding the battery type (or voltage) being recommended. My latest pH meter was one of the first of it's type in this country, that and the everchanging worldwide battery supply situation, could be a reason for the difference.
I think I'll be content to continue with the current situation.
This forum really is a great wealth of information.