How to connect to old Samba-server with new smbclient?

A Linux-based multimedia-box I have runs smbd, which reports its version as **3.0.30**. smbclient 4.10 used to be able to connect to it, but, after upgrading the client to **4.13.8**, I'm getting NT_STATUS_CONNECTION_DISCONNECTED immediately upon startup... I'm sure, this is due to some option being disabled in the latest versions of Samba -- but which one? Can I enable it back by editing smb.conf (how?), or is it removed completely and I need to downgrade the client (to 4.12?)? At debug level 9, here is, what I get:

Processing section "[global]"
doing parameter raw NTLMv2 auth = yes
lpcfg_do_global_parameter: WARNING: The "raw NTLMv2 auth" option is deprecated
doing parameter lanman auth = yes
lpcfg_do_global_parameter: WARNING: The "lanman auth" option is deprecated
doing parameter ntlm auth = yes
doing parameter log level = auth:1000
doing parameter workgroup = Xxxxxxx
doing parameter server string = Xxxxx Samba Server
doing parameter security = user
doing parameter client use spnego = yes
lpcfg_do_global_parameter: WARNING: The "client use spnego" option is deprecated
doing parameter hosts allow = 192.168.1. 127.
doing parameter load printers = yes
doing parameter guest account = nobody
doing parameter log file = /var/log/samba/log.%m
doing parameter max log size = 50
doing parameter socket options = SO_RCVBUF=8192 SO_SNDBUF=8192
doing parameter dns proxy = no
doing parameter unix charset = koi8-u
pm_process() returned Yes
lp_servicenumber: couldn't find homes
added interface bce1 ip=192.168.1.8 bcast=192.168.1.255 netmask=255.255.255.0
added interface ib0 ip=192.168.2.11 bcast=192.168.2.255 netmask=255.255.255.0
added interface ib1 ip=192.168.3.11 bcast=192.168.3.255 netmask=255.255.255.0
Netbios name list:-
my_netbios_names="xxxx"
Client started (version 4.13.8).
Opening cache file at /var/db/samba4/gencache.tdb
sitename_fetch: No stored sitename for realm ''
name dune1#20 found.
Connecting to 192.168.1.167 at port 445
Socket options:
        SO_KEEPALIVE = 0
        SO_REUSEADDR = 0
        SO_BROADCAST = 0
        TCP_NODELAY = 0
        TCP_KEEPCNT = 8
        TCP_KEEPIDLE = 7200
        TCP_KEEPINTVL = 75
        IPTOS_LOWDELAY = 0
        IPTOS_THROUGHPUT = 0
        SO_REUSEPORT = 0
        SO_SNDBUF = 8192
        SO_RCVBUF = 8192
        SO_SNDLOWAT = 2048
        SO_RCVLOWAT = 1
        SO_SNDTIMEO = 0
        SO_RCVTIMEO = 0
 session request ok
protocol negotiation failed: NT_STATUS_CONNECTION_DISCONNECTED

After downgrading back to 4.10, the above verbose logging ends with the proper password prompt:

Connecting to 192.168.1.167 at port 445
Socket options:
        SO_KEEPALIVE = 0
        SO_REUSEADDR = 0
        SO_BROADCAST = 0
        TCP_NODELAY = 0
        TCP_KEEPCNT = 8
        TCP_KEEPIDLE = 7200
        TCP_KEEPINTVL = 75
        IPTOS_LOWDELAY = 0
        IPTOS_THROUGHPUT = 0
        SO_REUSEPORT = 0
        SO_SNDBUF = 8192
        SO_RCVBUF = 8192
        SO_SNDLOWAT = 2048
        SO_RCVLOWAT = 1
        SO_SNDTIMEO = 0
        SO_RCVTIMEO = 0
 session request ok
 negotiated dialect[NT1] against server[dune1]
Enter Xxxx\xx's password:

Has the "**NT1 dialect**" been removed from Samba-4.12 and 4.13? Can I enabled it back through config-file?