Unregistered trusts (not registered under section 12AA) can indeed carry forward their losses to subsequent years. These carried-forward losses can then be set off against the trust's income in any future year. Crucially, to be eligible for this benefit, the tax return must be filed within the stipulated due date.
Whether Unregistered Trust (not registered u/s12AA) can be carry forward its loss to next & same carry forwarded loss can be set off against income of the trust of any year.