Priority between existing and subsequently adopted general by laws

Not sure if this has been previously addressed.  However my basic concern is determining priority between existing by laws and subsequently adopted general by laws.

My building noticeboard currently shows the previously adopted by law for keeping of animals (1988) as overriding all reference to keeping of animals in the subsequently adopted general by laws (1996).

The general by laws include by law 16(2) which specifies that ‘The owners corporation must not unreasonably withhold its approval of the keeping of an animal on a lot or common property’.

The previously adopted by law had no provision to grant approval based on  reasonability.   As such, my concerns are as follows:

1) Does a previously adopted by law override some (or all) reference to the same subject in a subsequently adopted set of general by laws, or vice versa?

2) Does the wider basis for determining approval of an action as set out in a subsequently adopted set of general by laws still stand, or is it over ridden by the tighter restrictions of previously adopted by laws?