Preexisting condition exclusions

My wife is currently covered on one of the older BCBS policies.  She has two long standing medical conditions which result in some significant medical expenses every year.

We have looked at switching her to one of the newer "metallic" policies but note that some of the Summary of Benefits for those policies still talk about possible exclusions for preexisting conditions.  We thought preexisting condition exclusions were a thing of the past.  Are they still applicable to the metallic plan policies?

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