samba-replacment issue network environment

but the smbd comand show me the old version?

That can be normal. The 'replacement package' doesn't actually replace the smbd binary, but installs a second on (in /opt/bin/ in contrast to the firmware /usr/bin). The startscript (/opt/etc/init.d/99sambareplacement) hooks the samba startscript (/etc/init.d/samba.sh) to start the optware smbd instead of the firmware one. Which binary actually will be called when you execute 'smbd —version' depends on your PATH.

I can connect to samba shares manual, but in the network environment i cant see the zyxel NAS. It works again If I activate smb 1.0 client option.

In smb 1.0 the peer discovery was based on netbios broadcasts. In smb 2 that is changed, it's now dependent on mDNS. Apparently the stock firmware doesn't implement this, and the new samba doesn't either, or it's not configured.

Sorry, that package was actually a quickfix for someone else who couldn't use smb1 anymore due to a company laptop with policies. When other people asked me for the script I provided it for download. But it's not very mature.

When you really need network discovery, you could look if you can install an Entware avahi daemon, or something like that.