Details of net-misc/networkmanager:

The ${PN} system configuration file has moved to a new location.
You must migrate your settings from ${EROOT}/etc/NetworkManager/nm-system-settings.conf
to ${EROOT}/etc/NetworkManager/NetworkManager.conf
After doing so, you can remove ${EROOT}/etc/NetworkManager/nm-system-settings.conf
You seem to use 'ifnet' plugin in ${EROOT}/etc/NetworkManager/NetworkManager.conf
Since it won't be used, you will need to stop setting ifnet plugin there.
psk-flags=1
You have psk-flags=1 setting in above files, you will need to
either reconfigure affected networks or, at least, set the flag
value to '0'.
You have enabled USE=dhcpcd, but NetworkManager since version 1.20 defaults to
the internal DHCP client. If the internal client works for you, and you're happy
with, the alternative USE flags can be disabled. If you want to use dhcpcd, then
you need to tweak the main.dhcp configuration option to use one of them instead
of internal.
Systemd defaults to DNSSEC=allow-downgrade. This can break some captive portals.
Until upstream solves this issue, you may need to disable it by setting DNSSEC=no
at /etc/systemd/resolved.conf
You have enabled USE=wext. Note that wext has been deprecated and support for
it will be removed in a future release.

The ${PN} system configuration file has moved to a new location.
You must migrate your settings from ${EROOT}/etc/NetworkManager/nm-system-settings.conf
to ${EROOT}/etc/NetworkManager/NetworkManager.conf
After doing so, you can remove ${EROOT}/etc/NetworkManager/nm-system-settings.conf
You seem to use 'ifnet' plugin in ${EROOT}/etc/NetworkManager/NetworkManager.conf
Since it won't be used, you will need to stop setting ifnet plugin there.
psk-flags=1
You have psk-flags=1 setting in above files, you will need to
either reconfigure affected networks or, at least, set the flag
value to '0'.
You have enabled USE=dhcpcd, but NetworkManager since version 1.20 defaults to
the internal DHCP client. If the internal client works for you, and you're happy
with, the alternative USE flags can be disabled. If you want to use dhcpcd, then
you need to tweak the main.dhcp configuration option to use one of them instead
of internal.
Systemd defaults to DNSSEC=allow-downgrade. This can break some captive portals.
Until upstream solves this issue, you may need to disable it by setting DNSSEC=no
at /etc/systemd/resolved.conf
You have enabled USE=wext. Note that wext has been deprecated and support for
it will be removed in a future release.

The ${PN} system configuration file has moved to a new location.
You must migrate your settings from ${EROOT}/etc/NetworkManager/nm-system-settings.conf
to ${EROOT}/etc/NetworkManager/NetworkManager.conf
After doing so, you can remove ${EROOT}/etc/NetworkManager/nm-system-settings.conf
You seem to use 'ifnet' plugin in ${EROOT}/etc/NetworkManager/NetworkManager.conf
Since it won't be used, you will need to stop setting ifnet plugin there.
psk-flags=1
You have psk-flags=1 setting in above files, you will need to
either reconfigure affected networks or, at least, set the flag
value to '0'.
You have enabled USE=dhcpcd, but NetworkManager since version 1.20 defaults to
the internal DHCP client. If the internal client works for you, and you're happy
with, the alternative USE flags can be disabled. If you want to use dhcpcd, then
you need to tweak the main.dhcp configuration option to use one of them instead
of internal.
Systemd defaults to DNSSEC=allow-downgrade. This can break some captive portals.
Until upstream solves this issue, you may need to disable it by setting DNSSEC=no
at /etc/systemd/resolved.conf
You have enabled USE=wext. Note that wext has been deprecated and support for
it will be removed in a future release.

The ${PN} system configuration file has moved to a new location.
You must migrate your settings from ${EROOT}/etc/NetworkManager/nm-system-settings.conf
to ${EROOT}/etc/NetworkManager/NetworkManager.conf
After doing so, you can remove ${EROOT}/etc/NetworkManager/nm-system-settings.conf
You seem to use 'ifnet' plugin in ${EROOT}/etc/NetworkManager/NetworkManager.conf
Since it won't be used, you will need to stop setting ifnet plugin there.
psk-flags=1
You have psk-flags=1 setting in above files, you will need to
either reconfigure affected networks or, at least, set the flag
value to '0'.
You have enabled USE=dhcpcd, but NetworkManager since version 1.20 defaults to
the internal DHCP client. If the internal client works for you, and you're happy
with, the alternative USE flags can be disabled. If you want to use dhcpcd, then
you need to tweak the main.dhcp configuration option to use one of them instead
of internal.

The ${PN} system configuration file has moved to a new location.
You must migrate your settings from ${EROOT}/etc/NetworkManager/nm-system-settings.conf
to ${EROOT}/etc/NetworkManager/NetworkManager.conf
After doing so, you can remove ${EROOT}/etc/NetworkManager/nm-system-settings.conf
You seem to use 'ifnet' plugin in ${EROOT}/etc/NetworkManager/NetworkManager.conf
Since it won't be used, you will need to stop setting ifnet plugin there.
psk-flags=1
You have psk-flags=1 setting in above files, you will need to
either reconfigure affected networks or, at least, set the flag
value to '0'.
You have enabled USE=dhclient and/or USE=dhcpcd, but NetworkManager since
version 1.20 defaults to the internal DHCP client. If the internal client
works for you, and you're happy with, the alternative USE flags can be
disabled. If you want to use dhclient or dhcpcd, then you need to tweak
the main.dhcp configuration option to use one of them instead of internal.
Note that dhclient has been deprecated and support for that will be removed
in a future release.