di propiti sunt: there is no doubt about the reading of the first two words (cf. 466) and they must be part of a standard expression of optimism; given that propitius is often used of the gods (cf. OLD, s.v.) it would be perverse to understand di as anything other than the contracted form of dei. What follows is less certain. The first two letters look like fu but what follows seems clearly to be n and after that t is possible; it may be that the apparent cross-bar of f is illusory.
Nonis: there is a very faint trace following which might be the beginning of a month-name (probably omitted in 236.3, however) but no reading could be regarded as more than very speculative. We have no way of calculating the number of letters likely to be lost at the right. The sender may be saying something like Vindolandae, si di propiti sunt, (ego) sum futurus Nonis [month-name].
uelim: see OLD, s.v.10. The traces at the end of the line are too exiguous to enable us to attempt a reading.
explices: for the uses of this verb in the Vindolanda texts see 343.i.4, 316.margin 1, 301.i.5 and notes ad locc. The financial usage is well-attested but here it is perhaps safest to take it in its common meaning "explain". The traces at the end of the line are very faint; frat[er may be possible.
Seuero: there are two other people with this name in the Vindolanda texts, Vettius Severus, the recipient of a letter and perhaps a prefect (305.back), and the writer of 301 who was a slave. Neither seems likely to be identical with the person here mentioned.
explica: the reading of l is difficult; we would need to ignore apparent ink at the foot of l and assume that the mark at the top right of i is not ink.
salut[: if this is correct we suggest restoring something like salut[a (a me) con-/tuberna[les tuos/meos.
The first traces appear to be ].bas but ]abis (salut]abis?) is perhaps not impossible. For the abbreviation of uale see also 312.ii.12, 343.iv.45, 505.
Perhaps frater karissim]e.
This is written on an upward slant and must be the name of the sender. For Fatalis see the introduction. The trace of the first surviving letter looks most like l, which would rule out Fla]uio, and would be very hard to reconcile with Clau]dio. Of the common gentilicia, Iu]lio is easier to read. Note the remark of Tomlin (1992), 151 that in Britain this gentilicium is almost always held by legionary centurions or rankers.