For the first time in nearly a decade, a new signature appears on the letters sent to would-be Mormon missionaries — that of Russell M. Nelson.

With the death last week of President Thomas S. Monson, Nelson became the senior leader in The Church of Jesus Christ of Latter-day Saints. It became Nelson’s responsibility to sign 1,150 “calls” in the characteristic “white envelopes” to full-time missionaries.

These letters, printed on the Quorum of the Twelve Apostles letterhead, contain the mission assignments for young men and women and senior couples, an LDS Church news release said, “including the date they will report to one of the church’s 15 missionary training centers around the world.”

“Even when there’s an impending change in church leadership, the work of the church moves forward,” Nelson said in the release. “We don’t want to have our prospective missionaries wait for their calling any longer than is necessary for this much-anticipated milestone in their lives.”

During Monson’s 10-year tenure, the Utah-based faith called 410,442 full-time missionaries, which represents “roughly three of every 10 missionaries who have served since the church was organized in 1830.”

In 2012, the faith lowered the minimum age of young missionaries from 19 to 18 for “elders” (males) and from 21 to 19 for “sisters” (females), which dramatically increased the missionary corps from 58,000 to nearly 90,000.

Today, the church has nearly 67,000 missionaries, the release said, serving in 421 missions around the globe.

Sometime after Monson’s funeral, set for noon Friday in the Conference Center in downtown Salt Lake City, the remaining Mormon apostles are expected to meet and select a new church president.

As the longest-tenured apostle, Nelson, 93, is widely expected to become the 17th president of the nearly 16 million-member LDS Church.