Can I use old stamps after price increase?

Related questions

1. Do things ship on Saturday?
2. Is BNZ NZ owned?
3. What is first overnight vs Priority Overnight?
4. Are parcels delivered on Saturday?
5. Are stamps going up in 2019?
6. How thick can an envelope be?
7. Does Post deliver on a Saturday?
8. Is ASB Bank NZ owned?
9. What days do NZ Post delivery?
10. What time do packages get delivered?

Tags

1. #after
2. #mounting
3. #before
4. #january
5. #effect
6. #still
7. #seeking
8. #increase
9. #cents
10. #first
11. #stamps
12. #valid
13. #class
14. #postal
15. #purchased
16. #forever
17. #stamp
18. #service
19. #price