I am not sure this is a bug or just my setup. I had some problems getting LT Alpha 8 running using Postgres 11. The airtime database was not being created in the install script (tarball). After some digging I found it complained that my encoding in locales was wrong and I should be using Latin and not UTF8. There was nothing at all wrong with my locales (at least they look the same as in a working LT in Xenial). Postgres’ templates are set to LATIN so I fixed the templates to UTF8, not ideal but it worked. If you use Postgres for anything other than LT then I would not advise this. I found other suggested fixes in various websites, but none worked in Postgres 11. This did.
Using PSQL (actually I used ‘en_GB.UTF8’)
update pg_database set encoding = 6, datcollate = ‘en_US.UTF8’, datctype = ‘en_US.UTF8’ where datname = ‘template0’;
update pg_database set encoding = 6, datcollate = ‘en_US.UTF8’, datctype = ‘en_US.UTF8’ where datname = ‘template1’;
Then I re-ran the install and it all worked.