1. schema_signature same for every install
2. Make script where Database ENGINE is InnoDB
3. Don't convert ostic.sql and languages files to utf8
4. PHP REQUIREMENT LINK : https://osticket.com/download/ and also check include/class.setup.php
5. Download and update language from "https://osticket.com/download/#ostLang"
6. Check language update in next version(In 1.14.2 languages weren't properly updated)
7. If language packs doesn't download from site. Try to download using following URL depending upon script version.
https://s3.amazonaws.com/downloads.osticket.com/lang/1.14.x/[[LANG_CODE]].phar (languages are not available for 1.15, 1.16)