Imam an-Nawāwi, may Allah have mercy upon him said:

Issues related to the two ‘eids. The first – our aśhāb said: It is muśtahab (recommended) for one’s enlivening (ihyā’) of the two nights of ‘ēid with prayers and other acts of worship. Our aśhāb made hujja for this with the hadīth of Abū Umāma from the prophet, Salutations of Allah and Peace upon him, “One who does ihyā’ of the nights of the two ‘ēids, his heart will not die on the day when hearts die.” In a narration of ash-Shāfi’ie and Ibnu Maja “One who gets up on the two nights of ‘ēid to seek reward (ihtisāban) for the sake of Allah Most High, his heart will not die.” narrated by Abū Darda’ as a mauqūf hadīth. And it was narrated from the earlier narration of Abū Umāma as a mauqūf hadīth, and as a marfū’ hadīth as previously mentioned. All the chains are however, dha’īf (weak). Ash-Shafi’ī said in the Umm,
It has reached us that it is said “Du’a (Supplications) are certainly accepted on five nights. They are the nights of Jum’a (Friday), the Adhhā,  the Fitr, the first of Rajab and the middle of Sha’bān. Ash-Shāfi’ī said:  Ibrahim Bin Muhammad, narrated to us saying ” I saw the mashyakha (sheikhs) from the best of the people of Madina showed up at the mosque of the Prophet, Salutations and Peace of Allah upon him, on the nights of the two ‘ēids, and they made du’ā (supplications) and aźkār (remembrance) of Allah Most High until a portion of the night passed.” Ash-Shafi’ī said: it has reached us that Ibnu ‘Umar used to do ihyā’ of the night of Nahr (slaughtering).  Ash-Shāfi’ī said: I considered it muśtahab all that was transmitted with regard to these nights without considering them as fardh (obligatory). This is the end of the quote of ash-Shafi’ī.
Ash-Shāfi’ī and the aśhāb considered the ihyā’ of the mentioned nights as muśtahab even though the hadīth is dha’īf (weak). This is due to what has preceded in the earlier part of the book that the hadīths of fadhāil (virtues) is treated with tasāmuh (less stringent conditions imposed) and its’ ‘amal is made in accordance with its weakness.

Condition of Ihyā’

The śahīh view is that the virtue of this ihyā’ is not realized except by getting up for worship for the majority of the night. It is also said that it is already realized by doing so for just a portion of it and this view is supported by what was quoted by ash-Shāfi’iī with regard to the mashyakha of Madina. Al-Qadhī Husain, on the other hand, quoted from Ibnu ‘Abbās that the ihyā’ of the night of ‘ēid is realized by one praying ‘Īshā’ in congregation and have ‘azm (resolution) to pray śubh in congregation. The mukhtār (relied upon) view is as mentioned earlier.
And Allah knows best.