diff --git a/src/aggregators/coevolve.jl b/src/aggregators/coevolve.jl
index 795de02e..e3aa5f7f 100644
--- a/src/aggregators/coevolve.jl
+++ b/src/aggregators/coevolve.jl
@@ -146,7 +146,8 @@ function aggregate(aggregator::Coevolve, u, p, t, end_time, constant_jumps,
 end
 
 # set up a new simulation and calculate the first jump / jump time
-function initialize!(p::CoevolveJumpAggregation, integrator, u, params, t)
+function initialize!(p::CoevolveJumpAggregation, integrator::DiffEqBase.DEIntegrator, u,
+                     params, t)
     p.end_time = integrator.sol.prob.tspan[2]
     fill_rates_and_get_times!(p, u, params, t)
     generate_jumps!(p, integrator, u, params, t)
diff --git a/src/aggregators/direct.jl b/src/aggregators/direct.jl
index 028e5603..06efcd37 100644
--- a/src/aggregators/direct.jl
+++ b/src/aggregators/direct.jl
@@ -45,7 +45,8 @@ function aggregate(aggregator::DirectFW, u, p, t, end_time, constant_jumps,
 end
 
 # set up a new simulation and calculate the first jump / jump time
-function initialize!(p::DirectJumpAggregation, integrator, u, params, t)
+function initialize!(p::DirectJumpAggregation, integrator::DiffEqBase.DEIntegrator, u,
+                     params, t)
     p.end_time = integrator.sol.prob.tspan[2]
     generate_jumps!(p, integrator, u, params, t)
     nothing
diff --git a/src/aggregators/directcr.jl b/src/aggregators/directcr.jl
index b9aea31c..29243df4 100644
--- a/src/aggregators/directcr.jl
+++ b/src/aggregators/directcr.jl
@@ -85,7 +85,8 @@ function aggregate(aggregator::DirectCR, u, p, t, end_time, constant_jumps,
 end
 
 # set up a new simulation and calculate the first jump / jump time
-function initialize!(p::DirectCRJumpAggregation, integrator, u, params, t)
+function initialize!(p::DirectCRJumpAggregation, integrator::DiffEqBase.DEIntegrator, u,
+                     params, t)
     p.end_time = integrator.sol.prob.tspan[2]
 
     # initialize rates
diff --git a/src/aggregators/frm.jl b/src/aggregators/frm.jl
index a4802e17..ccfc1466 100644
--- a/src/aggregators/frm.jl
+++ b/src/aggregators/frm.jl
@@ -45,7 +45,8 @@ function aggregate(aggregator::FRMFW, u, p, t, end_time, constant_jumps,
 end
 
 # set up a new simulation and calculate the first jump / jump time
-function initialize!(p::FRMJumpAggregation, integrator, u, params, t)
+function initialize!(p::FRMJumpAggregation, integrator::DiffEqBase.DEIntegrator, u,
+                     params, t)
     p.end_time = integrator.sol.prob.tspan[2]
     generate_jumps!(p, integrator, u, params, t)
     nothing
diff --git a/src/aggregators/nrm.jl b/src/aggregators/nrm.jl
index 8e086173..38411dcf 100644
--- a/src/aggregators/nrm.jl
+++ b/src/aggregators/nrm.jl
@@ -60,7 +60,8 @@ function aggregate(aggregator::NRM, u, p, t, end_time, constant_jumps,
 end
 
 # set up a new simulation and calculate the first jump / jump time
-function initialize!(p::NRMJumpAggregation, integrator, u, params, t)
+function initialize!(p::NRMJumpAggregation, integrator::DiffEqBase.DEIntegrator, u,
+                     params, t)
     p.end_time = integrator.sol.prob.tspan[2]
     fill_rates_and_get_times!(p, u, params, t)
     generate_jumps!(p, integrator, u, params, t)
diff --git a/src/aggregators/rdirect.jl b/src/aggregators/rdirect.jl
index 70534c17..72a52a3d 100644
--- a/src/aggregators/rdirect.jl
+++ b/src/aggregators/rdirect.jl
@@ -64,7 +64,8 @@ function aggregate(aggregator::RDirect, u, p, t, end_time, constant_jumps,
 end
 
 # set up a new simulation and calculate the first jump / jump time
-function initialize!(p::RDirectJumpAggregation, integrator, u, params, t)
+function initialize!(p::RDirectJumpAggregation, integrator::DiffEqBase.DEIntegrator, u,
+                     params, t)
     p.end_time = integrator.sol.prob.tspan[2]
     fill_rates_and_sum!(p, u, params, t)
     p.max_rate = maximum(p.cur_rates)
diff --git a/src/aggregators/rssa.jl b/src/aggregators/rssa.jl
index 8f6ed907..91da0d7a 100644
--- a/src/aggregators/rssa.jl
+++ b/src/aggregators/rssa.jl
@@ -85,7 +85,8 @@ function aggregate(aggregator::RSSA, u, p, t, end_time, constant_jumps,
 end
 
 # set up a new simulation and calculate the first jump / jump time
-function initialize!(p::RSSAJumpAggregation, integrator, u, params, t)
+function initialize!(p::RSSAJumpAggregation, integrator::DiffEqBase.DEIntegrator,
+                     u, params, t)
     p.end_time = integrator.sol.prob.tspan[2]
     set_bracketing!(p, u, params, t)
     generate_jumps!(p, integrator, u, params, t)
diff --git a/src/aggregators/rssacr.jl b/src/aggregators/rssacr.jl
index dc7f42a6..d24f40ef 100644
--- a/src/aggregators/rssacr.jl
+++ b/src/aggregators/rssacr.jl
@@ -102,7 +102,8 @@ function aggregate(aggregator::RSSACR, u, p, t, end_time, constant_jumps,
 end
 
 # set up a new simulation and calculate the first jump / jump time
-function initialize!(p::RSSACRJumpAggregation, integrator, u, params, t)
+function initialize!(p::RSSACRJumpAggregation, integrator::DiffEqBase.DEIntegrator,
+                     u, params, t)
     p.end_time = integrator.sol.prob.tspan[2]
     set_bracketing!(p, u, params, t)
 
diff --git a/src/aggregators/sortingdirect.jl b/src/aggregators/sortingdirect.jl
index 078ac3c9..5577a7d7 100644
--- a/src/aggregators/sortingdirect.jl
+++ b/src/aggregators/sortingdirect.jl
@@ -64,7 +64,8 @@ function aggregate(aggregator::SortingDirect, u, p, t, end_time, constant_jumps,
 end
 
 # set up a new simulation and calculate the first jump / jump time
-function initialize!(p::SortingDirectJumpAggregation, integrator, u, params, t)
+function initialize!(p::SortingDirectJumpAggregation, integrator::DiffEqBase.DEIntegrator,
+                     u, params, t)
     p.end_time = integrator.sol.prob.tspan[2]
     fill_rates_and_sum!(p, u, params, t)
     generate_jumps!(p, integrator, u, params, t)
diff --git a/src/spatial/directcrdirect.jl b/src/spatial/directcrdirect.jl
index 56252829..657368f8 100644
--- a/src/spatial/directcrdirect.jl
+++ b/src/spatial/directcrdirect.jl
@@ -104,7 +104,8 @@ function aggregate(aggregator::DirectCRDirect, starting_state, p, t, end_time,
 end
 
 # set up a new simulation and calculate the first jump / jump time
-function initialize!(p::DirectCRDirectJumpAggregation, integrator, u, params, t)
+function initialize!(p::DirectCRDirectJumpAggregation, integrator::DiffEqBase.DEIntegrator,
+                     u, params, t)
     p.end_time = integrator.sol.prob.tspan[2]
     fill_rates_and_get_times!(p, integrator, t)
     generate_jumps!(p, integrator, params, u, t)
diff --git a/src/spatial/nsm.jl b/src/spatial/nsm.jl
index 422c2bf1..7d3a8aeb 100644
--- a/src/spatial/nsm.jl
+++ b/src/spatial/nsm.jl
@@ -92,7 +92,8 @@ function aggregate(aggregator::NSM, starting_state, p, t, end_time, constant_jum
 end
 
 # set up a new simulation and calculate the first jump / jump time
-function initialize!(p::NSMJumpAggregation, integrator, u, params, t)
+function initialize!(p::NSMJumpAggregation, integrator::DiffEqBase.DEIntegrator, u,
+                     params, t)
     p.end_time = integrator.sol.prob.tspan[2]
     fill_rates_and_get_times!(p, integrator, t)
     generate_jumps!(p, integrator, params, u, t)