The rules on e-cigarettes are changing
As of May, laws are going to be standardised across the EU, which restricts how big your liquid containers can be, and how much nicotine they're allowed to contain. There'll also be new rules on how you can advertise e-cigs too.
In the UK, this means the rules will be stricter, while in other countries, this standardisation will see rules being relaxed. If you live somewhere where vapes are banned, they'll now be available to you.
For UK readers, these changes mean that refill containers can be no bigger than 10ml, and cartridges can be no larger than 2ml. As for nicotine strength, the maximum from May will be 20mg. Also, rules are already in place in the UK, banning the sale of e-cigs to anyone who is under 18.
One of the new rules says that e-cigs and refill containers will need to have a mechanism which guarantees leak free refilling. Now, seeing as most leaks are caused by the user, rather than the device, it isn't clear what this actually means, but there you go.
There's also a potential for an outright ban, should a 'competent authority' thinks that any product presents a health risk, but it would need the backing of 3 EU member states.
All the new rules can be found here.