Ithimba lokuthuthukiswa kwemisila lisebenza ekukhishweni okukhulu okulandelayo kwalokhu kusabalalisa abaningi abakubiza nge-Anonymous OS.
Imisila i-4.0 ingene ku-beta muva nje futhi ingukukhishwa kokuqala ngaphansi kohlelo lwe-Debian 10 Buster., okusho ukuthi wonke noma iningi lamaphakeji afakwe kuqala abuyekezelwe ezinguqulweni zakamuva ukuxhasa izingxenye ezintsha zehadiwe, ikakhulukazi amakhadi emidwebo avela ku-AMD naseNvidia, kanye namakhompyutha we-Mac.
Imisila i-4.0 nayo inayo I-Thunderbolt 3 ukwesekwa kwedivayisi, manje esehlanganiswe nenguqulo yakamuva ye-GNOME 3, indawo yokuqhafaza ezofika ngokuzenzakalela kuMisila. Kunconywa ukuthi abasebenzisi abanedivayisi yeThunderbolt bahlole ukusetshenziswa ngokuzulazula ku-Amadivayisi> I-Thunderbolt ngaphakathi kwezilungiselelo ze-GNOME.
Ngakolunye uhlangothi, abasebenzisi be-Tails 4.0 bazokwazi ukuvula amavolumu aqhubekayo kusuka kwenye i-USB enomsila, engeza uhlelo lokusebenza oluphatha amafayili kuzintandokazi, khombisa i-applet ye-OpenPGP ngakwesokunxele kwesimo se-TOR, shintsha isithombe sangemuva sokungena ngemvume screen, bese usebenzisa amabhukumaka okuzenzakalelayo esipheqululini se-Tor.
Izicelo eziningi eze ngokuzenzakalela kuMsila zizosuswa ku-Tails 4.0. Lokhu kufaka phakathi uhlelo lokushicilela lweScribus nengxenye yeMath yeLibreOffice suite, engafakwa esigabeni seSoftware Eyengeziwe. Ngokwengeziwe, ithuluzi lokuphathwa kwephasiwedi leKeePassX lizothathelwa indawo yiKeePassXC.
Futhi kususwe ku-Tails 4.0 isiqalisi sasekhaya kusuka kudeskithophu nakuma-akhawunti we-Pidgin azenzakalelayo. Ungakwazi landa imisila 4.0 kusuka ekhasini elisemthethweni, kepha akunconywa ukusetshenziswa kwebhizinisi. Ukukhishwa kokugcina kufika ngo-Okthoba 22, 2019.