diff --git a/docs/requirements.txt b/docs/requirements.txt
index d3a6ed9576..597f7bc5dd 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,6 +1,6 @@
 -f https://download.pytorch.org/whl/cpu/torch-1.6.0%2Bcpu-cp37-cp37m-linux_x86_64.whl
 torch>=1.6
-pytorch-ignite==0.4.9
+pytorch-ignite==0.4.10
 numpy>=1.17
 itk>=5.2
 nibabel
diff --git a/monai/apps/auto3dseg/ensemble_builder.py b/monai/apps/auto3dseg/ensemble_builder.py
index 384cb629a3..d63ad398e1 100644
--- a/monai/apps/auto3dseg/ensemble_builder.py
+++ b/monai/apps/auto3dseg/ensemble_builder.py
@@ -214,7 +214,6 @@ def __init__(self, n_fold: int = 5):
         self.n_fold = n_fold
 
     def collect_algos(self):
-
         """
         Rank the algos by finding the best model in each cross-validation fold
         """
diff --git a/monai/apps/reconstruction/networks/nets/utils.py b/monai/apps/reconstruction/networks/nets/utils.py
index 15f06f638f..b97cdab786 100644
--- a/monai/apps/reconstruction/networks/nets/utils.py
+++ b/monai/apps/reconstruction/networks/nets/utils.py
@@ -23,7 +23,6 @@
 
 
 def reshape_complex_to_channel_dim(x: Tensor) -> Tensor:
-
     """
     Swaps the complex dimension with the channel dimension so that the network treats real/imaginary
     parts as two separate channels.
@@ -50,7 +49,6 @@ def reshape_complex_to_channel_dim(x: Tensor) -> Tensor:
 
 
 def reshape_channel_complex_to_last_dim(x: Tensor) -> Tensor:
-
     """
     Swaps the complex dimension with the channel dimension so that the network output has 2 as its last dimension
 
@@ -128,7 +126,6 @@ def reshape_batch_channel_to_channel_dim(x: Tensor, batch_size: int) -> Tensor:
 
 
 def complex_normalize(x: Tensor) -> Tuple[Tensor, Tensor, Tensor]:
-
     """
     Performs layer mean-std normalization for complex data. Normalization is done for each batch member
     along each part (part refers to real and imaginary parts), separately.
@@ -171,7 +168,6 @@ def complex_normalize(x: Tensor) -> Tuple[Tensor, Tensor, Tensor]:
 def divisible_pad_t(
     x: Tensor, k: int = 16
 ) -> Tuple[Tensor, Tuple[Tuple[int, int], Tuple[int, int], Tuple[int, int], int, int, int]]:
-
     """
     Pad input to feed into the network (torch script compatible)
 
@@ -234,7 +230,6 @@ def divisible_pad_t(
 def inverse_divisible_pad_t(
     x: Tensor, pad_sizes: Tuple[Tuple[int, int], Tuple[int, int], Tuple[int, int], int, int, int]
 ) -> Tensor:
-
     """
     De-pad network output to match its original shape
 
diff --git a/monai/auto3dseg/algo_gen.py b/monai/auto3dseg/algo_gen.py
index 2f30987dd8..b84fea4a22 100644
--- a/monai/auto3dseg/algo_gen.py
+++ b/monai/auto3dseg/algo_gen.py
@@ -19,7 +19,6 @@ class Algo:
     """
 
     def set_data_stats(self, *args, **kwargs):
-
         """Provide dataset (and summaries) so that the model creation can depend on the input datasets."""
         pass
 
diff --git a/monai/fl/client/client_algo.py b/monai/fl/client/client_algo.py
index 4cab0a4474..6afd78c437 100644
--- a/monai/fl/client/client_algo.py
+++ b/monai/fl/client/client_algo.py
@@ -9,71 +9,96 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import abc
+from typing import Optional
 
 from monai.fl.utils.exchange_object import ExchangeObject
 
 
-class ClientAlgo(abc.ABC):
+class ClientAlgo:
     """
     objective: provide an abstract base class for defining algo to run on any platform.
     To define a new algo script, subclass this class and implement the
     following abstract methods:
 
-        - #Algo.train()
-        - #Algo.get_weights()
-        - #Algo.evaluate()
+        - self.train()
+        - self.get_weights()
+        - self.evaluate()
 
-    initialize() and finalize() can be optionally be implemented to help with lifecycle management of the object.
+    initialize(), abort(), and finalize() can be optionally be implemented to help with lifecycle management
+    of the class object.
     """
 
-    def initialize(self, extra=None):
-        """call to initialize the ClientAlgo class"""
+    def initialize(self, extra: Optional[dict] = None):
+        """
+        Call to initialize the ClientAlgo class
+
+        Args:
+            extra: optional extra information, e.g. dict of `ExtraItems.CLIENT_NAME` and/or `ExtraItems.APP_ROOT`
+        """
         pass
 
-    def finalize(self, extra=None):
-        """call to finalize the ClientAlgo class"""
+    def finalize(self, extra: Optional[dict] = None):
+        """
+        Call to finalize the ClientAlgo class
+
+        Args:
+            extra: optional extra information
+        """
         pass
 
-    def abort(self, extra=None):
-        """call to abort the ClientAlgo training or evaluation"""
+    def abort(self, extra: Optional[dict] = None):
+        """
+        Call to abort the ClientAlgo training or evaluation
+
+        Args:
+            extra: optional extra information
+        """
+
         pass
 
-    @abc.abstractmethod
-    def train(self, data: ExchangeObject, extra=None) -> None:
+    def train(self, data: ExchangeObject, extra: Optional[dict] = None) -> None:
         """
-        objective: train network and produce new network from train data.
-        # Arguments
-        data: ExchangeObject containing current network weights to base training on.
+        Train network and produce new network from train data.
+
+        Args:
+            data: ExchangeObject containing current network weights to base training on.
+            extra: optional extra information
+
+        Returns:
+            None
         """
-        raise NotImplementedError
+        raise NotImplementedError(f"Subclass {self.__class__.__name__} must implement this method.")
 
-    @abc.abstractmethod
-    def get_weights(self, extra=None) -> ExchangeObject:
+    def get_weights(self, extra: Optional[dict] = None) -> ExchangeObject:
         """
-        objective: get current local weights or weight differences
+        Get current local weights or weight differences
 
-        # Returns
-        ExchangeObject: current local weights or weight differences.
+        Args:
+            extra: optional extra information
 
-        # Example returns ExchangeObject, e.g.::
+        Returns:
+            ExchangeObject: current local weights or weight differences.
+
+        ExchangeObject example::
 
             ExchangeObject(
                 weights = self.trainer.network.state_dict(),
                 optim = None,  # could be self.optimizer.state_dict()
                 weight_type = WeightType.WEIGHTS
             )
+
         """
-        raise NotImplementedError
+        raise NotImplementedError(f"Subclass {self.__class__.__name__} must implement this method.")
 
-    @abc.abstractmethod
-    def evaluate(self, data: ExchangeObject, extra=None) -> ExchangeObject:
+    def evaluate(self, data: ExchangeObject, extra: Optional[dict] = None) -> ExchangeObject:
         """
-        objective: get evaluation metrics on test data.
-        # Arguments
-        data: ExchangeObject with network weights to use for evaluation
+        Get evaluation metrics on test data.
+
+        Args:
+            data: ExchangeObject with network weights to use for evaluation
+            extra: optional extra information
 
-        # Returns
-        metrics: ExchangeObject with evaluation metrics.
+        Returns:
+            metrics: ExchangeObject with evaluation metrics.
         """
-        raise NotImplementedError
+        raise NotImplementedError(f"Subclass {self.__class__.__name__} must implement this method.")
diff --git a/monai/fl/client/monai_algo.py b/monai/fl/client/monai_algo.py
index 7f99b9ead4..36f9366d02 100644
--- a/monai/fl/client/monai_algo.py
+++ b/monai/fl/client/monai_algo.py
@@ -12,14 +12,13 @@
 import logging
 import os
 import sys
-from typing import TYPE_CHECKING, Optional
+from typing import Optional
 
 import torch
 
 import monai
 from monai.bundle import ConfigParser
 from monai.bundle.config_item import ConfigComponent, ConfigItem
-from monai.config import IgniteInfo
 from monai.fl.client.client_algo import ClientAlgo
 from monai.fl.utils.constants import (
     BundleKeys,
@@ -33,12 +32,7 @@
 )
 from monai.fl.utils.exchange_object import ExchangeObject
 from monai.networks.utils import copy_model_state, get_state_dict
-from monai.utils import min_version, optional_import
-
-if TYPE_CHECKING:
-    from ignite.engine import Events
-else:
-    Events, _ = optional_import("ignite.engine", IgniteInfo.OPT_IMPORT_VERSION, min_version, "Events")
+from monai.utils import min_version, require_pkg
 
 logging.basicConfig(stream=sys.stdout, level=logging.INFO, format="%(asctime)s - %(message)s")
 
@@ -93,6 +87,7 @@ def disable_ckpt_loaders(parser):
                     h["_disabled_"] = True
 
 
+@require_pkg(pkg_name="ignite", version="0.4.10", version_checker=min_version)
 class MonaiAlgo(ClientAlgo):
     """
     Implementation of ``ClientAlgo`` to allow federated learning with MONAI bundle configurations.
@@ -407,18 +402,13 @@ def abort(self, extra=None):
         Args:
             extra: Dict with additional information that can be provided by FL system.
         """
-
         self.logger.info(f"Aborting {self.client_name} during {self.phase} phase.")
         if isinstance(self.trainer, monai.engines.Trainer):
             self.logger.info(f"Aborting {self.client_name} trainer...")
-            self.trainer.terminate()
-            self.trainer.state.dataloader_iter = self.trainer._dataloader_iter
-
-            if self.trainer.state.iteration % self.trainer.state.epoch_length == 0:
-                self.trainer._fire_event(Events.EPOCH_COMPLETED)
+            self.trainer.interrupt()
         if isinstance(self.evaluator, monai.engines.Trainer):
             self.logger.info(f"Aborting {self.client_name} evaluator...")
-            self.evaluator.terminate()
+            self.evaluator.interrupt()
 
     def finalize(self, extra=None):
         """
@@ -426,10 +416,6 @@ def finalize(self, extra=None):
         Args:
             extra: Dict with additional information that can be provided by FL system.
         """
-
-        # TODO: finalize feature could be built into the MONAI Trainer class
-        if extra is None:
-            extra = {}
         self.logger.info(f"Terminating {self.client_name} during {self.phase} phase.")
         if isinstance(self.trainer, monai.engines.Trainer):
             self.logger.info(f"Terminating {self.client_name} trainer...")
diff --git a/monai/utils/misc.py b/monai/utils/misc.py
index 5b56dfc7bb..ae62f26635 100644
--- a/monai/utils/misc.py
+++ b/monai/utils/misc.py
@@ -535,7 +535,6 @@ def label_union(x: List) -> List:
 
 
 def prob2class(x, sigmoid: bool = False, threshold: float = 0.5, **kwargs):
-
     """
     Compute the lab from the probability of predicted feature maps
 
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 2568bf9c1e..6620c96384 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1,6 +1,6 @@
 # Full requirements for developments
 -r requirements-min.txt
-pytorch-ignite==0.4.9
+pytorch-ignite==0.4.10
 gdown>=4.4.0
 scipy
 itk>=5.2
diff --git a/setup.cfg b/setup.cfg
index 09219bfc32..31464f9d87 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -34,7 +34,7 @@ all =
     pillow
     tensorboard
     gdown>=4.4.0
-    pytorch-ignite==0.4.9
+    pytorch-ignite==0.4.10
     torchvision
     itk>=5.2
     tqdm>=4.47.0
@@ -67,7 +67,7 @@ tensorboard =
 gdown =
     gdown>=4.4.0
 ignite =
-    pytorch-ignite==0.4.9
+    pytorch-ignite==0.4.10
 torchvision =
     torchvision
 itk =