Setup gpg keys (all the release keys as used in the past): $ gpg --batch --keyserver keyserver.ubuntu.com --recv-keys 20691EEC35216C63CAF66CE1656408E390CFB1F5 gpg: keybox '/tmp/tmp.iaIflEL03S/pubring.kbx' created gpg: /tmp/tmp.iaIflEL03S/trustdb.gpg: trustdb created gpg: key 656408E390CFB1F5: public key "MongoDB 4.4 Release Signing Key <packaging@mongodb.com>" imported gpg: Total number processed: 1 gpg: imported: 1 $ gpg --batch --keyserver keyserver.ubuntu.com --recv-keys 39BD841E4BE5FB195A65400E6A26B1AE64C3C388 gpg: key 6A26B1AE64C3C388: public key "MongoDB 6.0 Release Signing Key <packaging@mongodb.com>" imported gpg: Total number processed: 1 gpg: imported: 1 $ gpg --batch --keyserver keyserver.ubuntu.com --recv-keys 9DA31620334BD75D9DCB49F368818C72E52529D4 gpg: key 68818C72E52529D4: public key "MongoDB 4.0 Release Signing Key <packaging@mongodb.com>" imported gpg: Total number processed: 1 gpg: imported: 1 $ gpg --batch --keyserver keyserver.ubuntu.com --recv-keys E162F504A20CDF15827F718D4B7C549A058F8B6B gpg: key 4B7C549A058F8B6B: public key "MongoDB 4.2 Release Signing Key <packaging@mongodb.com>" imported gpg: Total number processed: 1 gpg: imported: 1 $ gpg --batch --keyserver keyserver.ubuntu.com --recv-keys E58830201F7DD82CD808AA84160D26BB1785BA38 gpg: key 160D26BB1785BA38: public key "MongoDB 7.0 Release Signing Key <packaging@mongodb.com>" imported gpg: Total number processed: 1 gpg: imported: 1 $ gpg --batch --keyserver keyserver.ubuntu.com --recv-keys F5679A222C647C87527C2F8CB00A0BD1E2C63C11 gpg: key B00A0BD1E2C63C11: public key "MongoDB 5.0 Release Signing Key <packaging@mongodb.com>" imported gpg: Total number processed: 1 gpg: imported: 1 $ mkdir -p /etc/apt/keyrings $ gpg --batch --export 20691EEC35216C63CAF66CE1656408E390CFB1F5 39BD841E4BE5FB195A65400E6A26B1AE64C3C388 9DA31620334BD75D9DCB49F368818C72E52529D4 E162F504A20CDF15827F718D4B7C549A058F8B6B E58830201F7DD82CD808AA84160D26BB1785BA38 F5679A222C647C87527C2F8CB00A0BD1E2C63C11 > /etc/apt/keyrings/mongodb.gpg Setup the apt sources.list: $ echo 'deb [ signed-by=/etc/apt/keyrings/mongodb.gpg ] http://repo.mongodb.org/apt/ubuntu jammy/mongodb-org/testing multiverse' > '/etc/apt/sources.list.d/mongodb-org.list' $ # also the regular repo for other deps like mongo-org-shell $ echo 'deb [ signed-by=/etc/apt/keyrings/mongodb.gpg ] http://repo.mongodb.org/apt/ubuntu jammy/mongodb-org/7.0 multiverse' > '/etc/apt/sources.list.d/mongodb-7.0.list' Try to apt-get update: $ apt-get update Get:1 http://archive.ubuntu.com/ubuntu jammy InRelease [270 kB] ... Get:22 http://security.ubuntu.com/ubuntu jammy-security/restricted amd64 Packages [1059 kB] Get:23 http://repo.mongodb.org/apt/ubuntu jammy/mongodb-org/7.0 Release.gpg [866 B] Get:24 http://repo.mongodb.org/apt/ubuntu jammy/mongodb-org/testing Release.gpg [866 B] Ign:24 http://repo.mongodb.org/apt/ubuntu jammy/mongodb-org/testing Release.gpg Get:25 http://repo.mongodb.org/apt/ubuntu jammy/mongodb-org/7.0/multiverse amd64 Packages [10.8 kB] Reading package lists... W: GPG error: http://repo.mongodb.org/apt/ubuntu jammy/mongodb-org/testing Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 81B0EBBBADCEA95C E: The repository 'http://repo.mongodb.org/apt/ubuntu jammy/mongodb-org/testing Release' is not signed. With the same error for focal/mongodg-org/testing: W: GPG error: http://repo.mongodb.org/apt/ubuntu focal/mongodb-org/testing Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 81B0EBBBADCEA95C