Speculation is now running as to what to expect for 2018 and beyond. Shows from the 1971 Japanese tour or Southampton on Jan 22, 1973 seem be the most expected.* Both the Japanese tour and the Southhampton show are known to have been recorded, so they are the natural expectations.
But pay heed to Page's ten year plan.
In 2002 a European Union wide copyright law was brought into effect that harmonized copyright across the EU. That law gave a 70-year copyright to sound performances from the "date of release." However:
"if a recording is not published or communicated to the public, copyright lasts for 50 years from when the recording was made"Anything not protected by "making the recording available for sale, both physically and online, in sufficient quantity," (emphasis mine) are subject to "use to or lose it" provisions within the Copyright Act.
Led Zeppelin started performing in 1968, their first show being September 7, 1968. A recording of that show would have to be released by September 7th of this year to secure copyright. While it's not expected that anything from the first European tour was recorded in sufficient quality for a release (or at all), it is possible something exists from 1968. Furthermore, it is known that some shows from early 1969 do exist.
If your betting on what's coming, bet on something that is in imminent danger from the "use it or lose it" provision. When Jimmy Page says 10-years, that means Knebworth in 2019, not now. Expect both Japan and Southhampton University to be released, but not until closer to 2021.
*I originally wrote the Southampton show that is known to exist in multitrack format was the Southampton University show on March 11, 1971. This has been corrected.
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