The ABA's Model Rules for Professional Responsibility start with Rule 1.1: Competence:
A lawyer shall provide competent representation to a client. Competent representation requires the legal knowledge, skill, thoroughness and preparation reasonably necessary for the representation.
In 2012, the ABA added an eighth comment to this rule, which clarifies that rule 1.1 should be interpreted to mean that attorneys must maintain technological competence.
 To maintain the requisite knowledge and skill, a lawyer should keep abreast of changes in the law and its practice, including the benefits and risks associated with relevant technology, engage in continuing study and education and comply with all continuing legal education requirements to which the lawyer is subject.
Since then, 37 states have adopted the duty of technological competence, including Minnesota, and a few have gone further and require technology-related continuing legal education credits for members of the bar. This has raised the question of what kind of competence is required.
The most common areas this rule have been applied to relate to data security, and effective use of technologies commonly used in the practice of law (such as email, storage of documents, office software, etc). Increasingly, other areas of technology are being discussed in this context. For example, some consider an understanding of social media technologies a core competence for attorneys. Another common area is e-discovery.
As technology evolves and is implemented by lawyers, the actual requirements of the duty of technological competence will change. The mandate is to keep up with the trends.
Below are some resources to help you get started.