Just days after the releases of Mozilla Firefox 1.0.5 and Mozilla Thunderbird 1.0.5, it appears likely that
1.0.6 versions of the two applications could be coming as early as next week. It is understood that API changes in 1.0.5 unintentionally broke some extensions.
In comment 45 of bug 300028, Rafael Ebron said yesterday, "We received feedback on 1.0.5 from distributors and extension developers on API changes that affected them (not a security issue), so we're looking at a 1.0.6 to fix it." It is known that the Enigmail PGP extension for Thunderbird does not work in version 1.0.5.