Hi,
Seblod updates through updater.
2 sites were transferred "as is" to the new server. One I had to reinstall via Akeeba backup. All 3 of them I updated to J3.5.1 and I installed the latest Seblod updater though the Joomla 'upload files'. After that I opened the Joomla updater and went straight to the components->seblod->updater.
(I notice that it is important to go to the Joomla update page first before proceeding to the Seblod one, otherwise files to be updated don't always show up!)
After that I updated Seblod to 3.8.3 followed by all the other Seblod element. Everything worked out smoothly except that for every site I had to go in the list section and adapt all the 'view' links. Luckily I experimented on a parallel test site with updates of 2 sites to see what possible surprises were awaiting me.
Bernard
ps. on the previous hostingprovider I had problems with file/group ownership which never got resolved and generated similar complaints for Seblod as wel as other elements with the Joomla sites.