According to https://github.com/JuliaLang/julia/releases/tag/v0.6.3, 0.6.3 is available and is a bugfix release, so it should really be updated in Gentoo as well.
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=28e483383d8cce5578c91fedbe8db2ed8655fc32 commit 28e483383d8cce5578c91fedbe8db2ed8655fc32 Author: Matthias Maier <tamiko@gentoo.org> AuthorDate: 2018-07-01 04:04:00 +0000 Commit: Matthias Maier <tamiko@gentoo.org> CommitDate: 2018-07-01 04:11:30 +0000 dev-lang/julia: version bump to 0.6.3 Closes: https://bugs.gentoo.org/658196 Package-Manager: Portage-2.3.41, Repoman-2.3.9 dev-lang/julia/Manifest | 2 + dev-lang/julia/julia-0.6.3.ebuild | 194 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 196 insertions(+)