Digital transformation suggests a high degree of automation while managing social behavior and planning individual or collaborative activities. Most scheduling and planning solutions are based on time, task and resource management. In this work, we consider the scenarios of so-called “soft” planning, which assumes the exact timing of activities might be unknown and dependent on flexible conditions. We conceptualize the project with the help of such instruments as common-sense ontology, domain-specific ontology, software requirements visualization, and visual statechart formalism. This particular contribution focuses on the challenges of developing a mobile notification service for managing activities “pre-programmed” by the user, in which notifications are issued if the user enters a location suitable for implementing the desired deferred action. The suggested ontology-based model does not assume using or improving formal optimal time or task scheduling, but suggests an approach for informal practical computer-assisted decision-making involving typical scenarios appearing in everyday life. We piloted a number of prototypes for location-based user-oriented reminder setup and notification management, partially fitting the requirements and major scenarios of a soft planning system. Based on the experiments with the developed prototype apps for Android, we elicit a number of important aspects of further work towards achieving the location-based situational planning and notification management solutions adopted for practical use.