You can upgrade from 1.9.14 to 1.10 but the system requirements have changed for 1.10:I would recommend that you use php 5.6, 5.3 will not work, 5.4 and 5.5 might work but have security issues because they already have reached their end of live.I'm not sure which minimum mySQL Version is required for 1.10 but when the four byte character support (like emojis) will come into 1.1x  I think it will jump to mySQL 5.5.3

As @[deleted] notes you will need to upgrade PHP.  Everything else looks okay to me.

One thing should also be mentioned:additional language packs are not ready to use with 1.10.They have to be updated by the developers. It was mentioned that this happen in the next time.I would remove them before you upgrade.

There seems to be a general problem when a language pack was used before.Even when I try a fresh installation of 1.9.15, add a language pack (like the recent german language pack of osticket.com) and remove the language (before the upgrade to 1.10) the upgrade will not finish without errors.I get 6 DB Error #1146 entries like this one: Table 'osticket1915.ost_translation' doesn't exist---- Backtrace ----#0 (root)/include/mysqli.php(204): osTicket->logDBError('DB Error #1146', '[SELECT A1.* FR...')#1 (root)/include/class.orm.php(3133): db_query('SELECT A1.* FRO...', true, true)#2 (root)/include/class.orm.php(3180): MySqlExecutor->execute()#3 (root)/include/class.orm.php(1771): MySqlExecutor->getArray()#4 (root)/include/class.orm.php(1815): ModelInstanceManager->{closure}()#5 (root)/include/class.orm.php(1794): CallbackSimpleIterator->next()#6 (root)/include/class.orm.php(1803): CallbackSimpleIterator->rewind()#7 (root)/include/class.orm.php(1463): CallbackSimpleIterator->valid()#8 (root)/include/class.orm.php(1480): CachedResultSet->fillTo(9223372036854775807)#9 (root)/include/class.orm.php(1489): CachedResultSet->asArray()#10 (root)/include/class.translation.php(899): CachedResultSet->getIterator()#11 (root)/include/class.translation.php(920): CustomDataTranslation:('en_US')#12 (root)/include/class.list.php(396): CustomDataTranslation:('37eec2fe8f75003...')#13 (root)/include/class.list.php(209): DynamicList->getLocal('name_plural')#14 (root)/include/class.list.php(524): DynamicList->getPluralName()#15 : DynamicList:()#16 (root)/include/class.forms.php(567): call_user_func(Array)#17 (root)/include/class.forms.php(575): FormField:()#18 (root)/include/class.forms.php(1016): FormField:('text')#19 : FormField->getImpl(Object(DynamicFormField))#20 (root)/include/class.dynamic_forms.php(596): call_user_func_array(Array, Array)#21 (root)/include/class.dynamic_forms.php(1339): DynamicFormField->__call('getImpl', Array)#22 (root)/include/class.dynamic_forms.php(1339): DynamicFormField->getImpl(Object(DynamicFormField))#23 (root)/include/class.dynamic_forms.php(948): DynamicFormEntryAnswer->getField()#24 (root)/include/class.company.php(71): DynamicFormEntry->getAnswer('name')#25 (root)/include/staff/footer.inc.php(5): Company->__toString()#26 (root)/scp/upgrade.php(88): require('/opt/bitnami/ap...')#27 {main}

I must correct myself: the content of the table ost_translation is missing after the upgrade and there were some more errors in the system log. There are nine 1146 db errors and one 1054 db error.The db error 1054 shows that the column "extra" is missing in the staff table: Unknown column 'extra' in 'field list'

Hmm, this errors are maybe normal. Even when I never used a language pack, (made fresh install with 1.9.15) and upgrade to 1.10. Both types of error (1146 and 1054) are written to the system log (before the the upgrader log entries). Maybe the upgrade process causes this errors, after the upgrade entries no further errors are shown in the system log..