I've checked under the Q&A section. Apparently,the license is tied to the hardware. no way to add additional license, unlike the 5500 series where its one hardware, and license based.
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The answer is No. I had the same issue and had tyo purchase a 5508. Do not buy the 5508-25 and the 25 license upgrade. That method is mroe expensive. Buy the 5508-50 and you also can upgrade more license in the future.
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