Declension table of ?upāstra

Neuter	Singular	Dual	Plural
Nominative	upāstram	upāstre	upāstrāṇi
Vocative	upāstra	upāstre	upāstrāṇi
Accusative	upāstram	upāstre	upāstrāṇi
Instrumental	upāstreṇa	upāstrābhyām	upāstraiḥ
Dative	upāstrāya	upāstrābhyām	upāstrebhyaḥ
Ablative	upāstrāt	upāstrābhyām	upāstrebhyaḥ
Genitive	upāstrasya	upāstrayoḥ	upāstrāṇām
Locative	upāstre	upāstrayoḥ	upāstreṣu

Compound upāstra -

Adverb -upāstram -upāstrāt