Depending on the type of DTA which is signed, any DTA could be rendered obsolete. There are instances when a country updates its taxation system which will require updating of one or more tax treaties with other countries to prevent it from becoming obsolete.
DTA can be abolished if there are situations which are not favourable to the countries which are involved. The reasons for such an abolition may include tax evasion or avoidance by investors from a given country as well as any other legal reasons which may not be favourable to the DTA of the countries which are involved.