Sojourner Memo is a free Android app developed by akai_t, designed specifically for players of the popular game Ingress. This app helps players keep track of their daily hacks and ensures they don't miss any important ones.

With Sojourner Memo, players can easily register the date and time of their hacks and set up notifications to remind them when the next hack is due. The notification can be customized to be sent one hour before the next hack, and the time can be adjusted according to the player's preference.

The app provides a simple and intuitive interface for viewing, editing, and deleting hack dates and times. It also includes a widget that allows players to quickly update their hack schedule by tapping on it. Additionally, Sojourner Memo supports direct hack date and time registration from AndroidWear notifications.

One notable feature of Sojourner Memo is the caution point warning system. The widget portal changes color to indicate danger points, and players can receive notifications when they reach these points. By default, the widget color changes to either blue or green when registering a hack.

Overall, Sojourner Memo is a useful utility for Ingress players who want to keep track of their daily hacks and stay on top of their game.