New Hard compound will be introduced in Spain.

[Hampus Andersson]

Seems like a weird thing to do, never heard a team complain about the hard compound but apparently it will change.
Slightly more geared towards last years hard compound.

Following a discussion with the teams after the Bahrain GP, Formula One tyre supplier Pirelli has decided to make a change in the hard tyre. This means that as of the next event, the Spanish GP held at Circuit de Catalunya, the hard, orange striped tyre will be of a different type.
Pirelli’s motorsport director Paul Hembery said: “After evaluating tyre performance over the balance of the first four races, we took the decision – in consultation with all of the teams – to change the hard compound from Spain onwards, as we did in Barcelona two years ago when we also introduced a new hard tyre for the rest of the season."

Knowing that the new hard tyre will resemble more than of 2012, it will be harder than the specification used so far in 2013. Indeed, many teams were seeing very different levels in performance between the medium and hard tyres, with only the level of degradation being a differentiation.

"This latest version of the hard compound is much closer to the 2012 tyre, with the aim of giving the teams more opportunity to run a wider range of strategies in combination with the other compounds, which remain unchanged.”

http://www.f1technical.net/news/18354

 

[Bradley Vanian]

I think it has relevance to the punctures Massa and Hamilton had at Bahrain.

It isn't linked to anything Red Bull have said. Red Bull want the softer compounds to be harder or for the races to use the Harder Compounds instead of the Softer Compounds.

 

[Kartik Sri Harsha]

Increasing the Durability of HARD tire is welcomed to avoid the Problems we saw with Lewis and Felipe . But the soft tire life span must be increased.The durability of Soft tire is around 7 - 10 odd laps (Considering the Q) is very very low. They need to increase it for 60-70 Km so that teams can have Variety of Choice like last year where Mclaren mostly ran the Prime tire but the RBR, Ferrari,Lotus trio ran the Option tire along with Prime tire in their Stints

 

[Metalfreaky]

I actually agree with Kartik, altough I'm not 100% sure if it is the compound or the tire choice that is/was too aggressive.
But I'm definitely against a change of the compound during the season because it will favour some teams more than others which would be pretty unfair in my opinion. Only if all teams would give their "ok" I would agree to change something.