As has been announced several times (most recently at https://lists.wikimedia.org/pipermail/wikitech-l/2015-April/081559.html), the default continuation mode for action=query requests to api.php will be changing to be easier for new coders to use correctly.

The date is now set: we intend to merge the change to ride the deployment train at the end of June. That should be 1.26wmf12, to be deployed to test wikis on June 30, non-Wikipedias on July 1, and Wikipedias on July 2.

If your bot or script is receiving the warning about this upcoming change (as seen here, for example), it's time to fix your code!
Either of the above solutions may be tested immediately, you'll know it works because you stop seeing the warning.

I've compiled a list of bots that have hit the deprecation warning more than 10000 times over the course of the week May 23–29. If you are responsible for any of these bots, please fix them. If you know who is, please make sure they've seen this notification. Thanks.

AAlertBot
AboHeidiBot
AbshirBot
Acebot
Ameenbot
ArnauBot
Beau.bot
Begemot-Bot
BeneBot*
BeriBot
BOT-Superzerocool
CalakBot
CamelBot
CandalBot
CategorizationBot
CatWatchBot
ClueBot_III
ClueBot_NG
CobainBot
CorenSearchBot
Cyberbot_I
Cyberbot_II
DanmicholoBot
DeltaQuadBot
Dexbot
Dibot
EdinBot
ElphiBot
ErfgoedBot
Faebot
Fatemibot
FawikiPatroller
HAL
HasteurBot
HerculeBot
Hexabot
HRoestBot
IluvatarBot
Invadibot
Irclogbot
Irfan-bot
Jimmy-abot
JYBot
Krdbot
Legobot
Lowercase_sigmabot_III
MahdiBot
MalarzBOT
MastiBot
Merge_bot
NaggoBot
NasirkhanBot
NirvanaBot
Obaid-bot
PatruBOT
PBot
Phe-bot
Rezabot
RMCD_bot
Shuaib-bot
SineBot
SteinsplitterBot
SvickBOT
TaxonBot
Theo's_Little_Bot
W2Bot
WLE-SpainBot
Xqbot
YaCBot
ZedlikBot
ZkBot


--
Brad Jorsch (Anomie)
Software Engineer
Wikimedia Foundation