I recently updated my manjaro installation and now KMail exits at startup. I ran KMail from a terminal and saw the following output:

[0719/090639.040903:WARNING:stack_trace_posix.cc(699)] Failed to open file: /tmp/.glOy2gkD (deleted)
Error: No such file or directory
org.kde.pim.mailcommon: "The Email program encountered a fatal error and will terminate now"
org.kde.pim.akonadiserver: Received an invalid command: resetting connection
org.kde.pim.akonadicore: "QLocalSocket: Remote closed" "/tmp/akonadi-manjaro.TXuFEi/akonadiserver-ntf.socket"
org.kde.pim.akonadicore: Protocol version mismatch. Server version is newer ( 59 ) than ours ( 58 ). If you updated your system recently please restart all KDE PIM applications.
org.kde.pim.mailcommon: "The Email program encountered a fatal error and will terminate now.\nThe error was:\nProtocol version mismatch. Server version is newer (59) than ours (58). If you updated your system recently please restart all KDE PIM applications."

KDE Plasma 5.13.2
KDE Frameworks 5.47.0
QT 5.11.1

I'm rather new to KDE so I'm not certain how to address this issue.

is it difficult for you trying to downgrade to 5.12.6 ?

I'm afraid 5.13.x isn't fully integrated into distributions yet

have you asked Manjaro support directly ?

disclaimer: I never used Manjaro