Windows are boarded up, locks changed. No notice was received prior. Can't go to work due to all possessions being locked in the house. No underwear, toothbrush, etc. Child will miss school. Just paid May rent on the 7th or 8th.
Was behind on the rent, agreement entered to pay back rent. No new court proceedings were filed.The landlord sd it is not an "eviction", but a "ejection"

No matter what the landlord chooses to call it, it was an illegal eviction. Call the police. They will force the landlord to let you in, at least to get your things. Make arrangements to find a new place and move your stuff. Then file a lawsuit against your landlord.

What state? Laws vary.

He has to evict in any state, but the process will vary. Ejection might be if the police remove you for violence, not for not paying rent, and even that might not keep him from allowing you back in.
Call the police. They have to find him and get him to let you in, or force their way in, such as to find a lease or other proof that you live there.
He can, however, evict you anyway, after following proper procedure, whether you pay now or not, for not paying when required.

I just notice 'no new court proceedings were filed.' What exactly does that mean? If he was evicting you, he can still enter an agreement for back rent, and the eviction continues. Just because you are getting evicted doesn't mean you don't owe. If the final stage was the sheriff going with him to the house to allow the locks to be changed, that's the end. Your possessions cannot be taken or thrown out, and again, laws about that vary by state.

I just notice 'no new court proceedings were filed.' What exactly does that mean? ...

Good catch. OP needs to let us know the nature and outcome of any "old" court proceedings involving this situation.

And I also notice that the thread title suggests that the LL just acquired the property. If by chance this was a foreclosue, Federal law (https://www.askmehelpdesk.com/real-estate-law/paying-rent-when-property-foreclosure-316199.html) may require 90-day notice under these circumstances.

I agree with joy and AK, we can't make much out of this until we hear what was ordered as a result of that earlier court proceedings