A few years ago the IRS allowed a one time deferral of capital gains taxes. Does anyone know if that is still allowed?
You may be thinking of the old rule on your primary residence. The new rule is that if you lived in a home for at least two of the last five years, you can completely exclude $500,000 of gain ($250,000 if single).
On sales of other than your primary residence, you can defer gain thru a like-kind exchange but those can be complicated and I won’t even start to explain those rules.
That’s probably what I was thinking of. But for the life of me, I couldn’t remember how it went. A friend of mine recently sold a piece of property (no house) and had to pay taxes. But she had never heard of the rule. Apparently it won’t include her situation anyway. (Unless it is included in the “those can be complicated and I won’t even start to explain those rules” area. 
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There’s also a 1031 exchange, but that only applies to business and investment properties, in the case where you exchange for a “like-kind” property, as defined by the IRS.