Yes, 3 and I will continue to rejoice,
1 tc Although κανόνι (kanoni, “standard, rule”) is found in most witnesses, though in various locations in this verse (א2 D2 Ψ 075 Ï), it is almost surely a motivated reading, for it clarifies the cryptic τῷ αὐτῷ (tw autw, “the same”). Both the fact that the word floats, and that there are other variants which accomplish greater clarity by other means, strongly suggests the secondary nature of any of the longer readings here. Further, the shortest text has excellent and early support in Ì16,46 א* A B Ivid 6 33 1739 co, rendering it decidedly the preferred reading. The translation adds “standard” because of English requirements, not because of textual basis.
2 tn Grk “Nevertheless, to what we have attained, to the same hold fast.”
3 tn Or “But.” The conjunction ἀλλά (alla) may be emphatic or contrastive. If the former, the idea may be that Paul will continue rejoicing because of the proclamation of the gospel or because of his imminent release from prison (v. 19); if the latter, Paul is now turning his attention solely to this second reason to rejoice, viz., that he will soon be released from prison. In this latter view the clause should be translated, “But I will also rejoice since I know…”