Is absolute seeking of forgiveness sufficient to expiate all of a person’s sins, or is it necessary to specify them by praying for those who have been wronged?

Absolute seeking of forgiveness (istighfar mutlaq) is sufficient to expiate all sins if it is accompanied by the conditions of sincere repentance (tawbah nasuh), which are: regret for the sin, abstaining from it, and a firm resolve not to return to it, along with restoring injustices to their owners or seeking their absolution. The rights of people are not waived by seeking forgiveness and repentance alone. If the right pertains to one's honor and you fear that informing the right-holder would cause greater harm, then abundant seeking of forgiveness and supplication for them, and mentioning their good qualities, especially in the places where they were slandered, will suffice. Supplicating for Muslims or for one who has wronged you does not take the place of repentance or fulfilling people's rights, but it does hold reward.