That original preprint suffered a number of revisions until it was replaced in December 2007 by a much more ambitious claim, which he had been developing for one year in the form of a parallel manuscript. Since that time he has released evolving versions of two purported generalizations, following independent but complementary approaches, of his original argument. In the shortest of them (43 pages as of 2009), which he titles "Apology for the Proof of the Riemann Hypothesis" (using the word "apology" in the rarely used sense of apologia), he claims to use his tools on the theory of Hilbert spaces of entire functions to prove the Riemann hypothesis for Dirichlet L-functions (thus proving the generalized Riemann hypothesis) and a similar statement for the Euler zeta function, and even to be able to assert that zeros are simple. In the other one (57 pages), he claims to modify his earlier approach on the subject by means of spectral theory and harmonic analysis to obtain a proof of the Riemann hypothesis for Hecke L-functions, a group even more general than Dirichlet L-functions (which would imply an even more powerful result if his claim was shown to be correct). As of January 2016, his paper entitled "A proof of the Riemann Hypothesis" is 74 pages long, but does not conclude with a proof. A commentary on his attempt is available on the Internet.