What happens can vary as part of the deal. If you are a participant in the plan (active, term vested, or in pay), you should get an an Annual Funding Notice. For calendar year plans, if it's a single employer qualified plan, these should be sent by April 30 for the prior plan year. My knowledge of multiemployer plans is really rusty, so I can't for the life of me remember if there is an AFN requirement for multiemployer plans (often union plans).
Does the former employer have a current address for you? Do you have contact information for HR?