Norway’s Opera Software said it is reviewing its “strategic alternatives” following interest from a “number of parties”, as it warned that 2015 revenue will come in below its earlier expectations.

The company said that its review is expected to conclude in the second half of 2015.

For the full year, Opera is now expecting revenue of $600 million to $618 million, compared with previous guidance of $630 million to $650 million.

For the second quarter, it provided preliminary EBITDA figures of $29 million, at the low end of its guidance ($29 million to $34 million), on revenue of $146 million ($145 million to $155 million guidance).

It will provide further detail at a presentation later this week.

The trimmed forecast was attributed to “weaker than expected performance in the Mobile Advertising – 3rd Party Publisher business area, which is only partially offset by a stronger outlook in our Consumer (O&O and Tech Licensing) business area”.

Opera is perhaps best known for its mobile browser technology, but the company has also been bolstering its proposition in areas such as mobile advertising and cloud-based products for operators.

The company is also active in the app market, announcing on Friday the acquisition of Bemobi, a subscription-based mobile app and games discovery service in Latin America.