This is the 11602nd most frequent Russian word.
ежемесячного
"Monthly."
Here, 'ежемесячного' is in the genitive case, referring to 'of monthly' within the context of 'ощчета' (report).
Я получаю ежемесячного отчета о нашей работе.
I receive a monthly report about our work.
In this sentence, 'ежемесячного' modifies the noun 'платежа' (payment) and agrees in case and gender.
В соответствии с нашим контрактом, я отправляю вам ежемесячного платежа.
According to our contract, I send you a monthly payment.
The word 'ежемесячного' here is an adjective describing 'обновления' (updating), showing periodic necessity.