At last I have found time to update my portfolio. And also did it in my ProZ profile. The main problem with the old portfolio was that it was not very representative. I had plenty of old translations, but they were made in old times, when most customers used to come in person and bring the jobs in paper, so I lacked the source texts. And having a fresh look at sample translations I uploaded 2 years ago, I understood that it is somewhat strange that a translator specilizing in oil and gas translations has no oil and gas translations in the portfolio.
By the way, selecting samples for a portfolio is a good exercise to determine your specialization. You have to ask yourself two simple questions:
1) What kind of jobs a potential customer is likely to assign me because s/he sees examples of my expereince in this topic?
2) What kind of jobs I can do fast and without difficulty because I have a lot of experience in this topic?
That is the essence of specialization: the customer can expect good quality of translation, and you will spend on it less time and thus are able to earn more.