Wegen der Posting-Key Geschichte. Man muss nicht unbedingt das Master-Passwort ändern, man kann auch nur den Posting-Key ändern, mit folgendem Skript (basierend auf Beem) habe ich das heute mal erfolgreich getestet. Achtung, Verwendung auf eigene Gefahr!

from beem.blockchain import Blockchain
from beem.steem import Steem
from beem.account import Account
from beem.instance import set_shared_steem_instance
from beembase import operations
from beemgraphenebase.account import BrainKey, PrivateKey, PublicKey, PasswordKey

account_name = "abc123"
old_pwd = "P5GEHEIM"
brainKey = BrainKey()
new_pwd = "P" + str(brainKey.get_private_key())
print(new_pwd)

def update_posting_key(steem):
    account = Account(account_name, steem_instance=steem)

    key_auths = {}

    pk = PasswordKey(account_name, new_pwd, role='posting')
    key_auths['posting'] = format(pk.get_public_key(), steem.prefix)

    print("Neuer Privater Posting Key :")
    print(str(pk.get_private_key()))

    for role in ['owner', 'active', 'memo']:
        pk = PasswordKey(account_name, old_pwd, role=role)
        key_auths[role] = format(pk.get_public_key(), steem.prefix)

    op = operations.Account_update(**{
        "account": account["name"],
        'owner': {'account_auths': [],
            'key_auths': [[key_auths['owner'], 1]],
            "address_auths": [],
            'weight_threshold': 1},
        'active': {'account_auths': [],
            'key_auths': [[key_auths['active'], 1]],
            "address_auths": [],
            'weight_threshold': 1},
        'posting': {'account_auths': account['posting']['account_auths'],
            'key_auths': [[key_auths['posting'], 1]],
            "address_auths": [],
            'weight_threshold': 1},
        'memo_key': key_auths['memo'],
        "json_metadata": account['json_metadata'],
        "prefix": steem.prefix,
    })

    steem.finalizeOp(op, account, "owner")
    steem.broadcast()

pk = PasswordKey(account_name, old_pwd, role='owner')
owner_wif = pk.get_private_key()

stm = Steem(
    node = "https://anyx.io/",
    bundle=True, # Enable bundle broadcast
    keys=[owner_wif]
)

set_shared_steem_instance(stm)
update_posting_key(stm)