When do I have to exercise my call to get the dividend?

To be entitled to receive a dividend, shares must be settled on the record date (i.e., the shares must have been purchased or the call option exercised prior to the ex-dividend date)…

CONFIGURE AUTOMATIC EXERCISE OPTIONS FOR DIVIDENDS

You may use the FYI Automatic Actions tool to automatically exercise US dividend-related stock and ETF options. Once configured, IBKR's system will determine whether an early exercise of call options may be beneficial. The system will send a notification two days before the stock trades ex-dividend and if the determination remains favorable, automatically exercise the option early…

The most common instance of this will occur when an account holder held a short option position prior to the ex-dividend date. In the event a long options holder exercises the position prior to ex-dividend date, the short holder may be assigned. Such action may lead to an account holding a short stock position over the ex-dividend date and will therefore be charged the dividend…

If you are maintaining a settled short position in a U.S. security as of the close of business one business day prior to the Record Date (this is also one business day prior to the Ex-Dividend Date) you will be liable to the lender for the dividend. If you bought in the position thereafter, the trade would not settle in time for you to avoid that payment obligation…