[otrs] OTRS upgrade from 2.3 to 2.4 errors

Hi, I successfully upgrade otrs 2.3.4 to otrs 2.4.2 but when i login to otrs i'm getting following erros under my error log, i have attached the log for your reference, does any one know how to fix them up or still those are known bugs under OTRS 2.4.2 version. Lakshan